GIFT OF
MICHAEL REESE
CHAPMAN'S
BLOWPIPE PRACTICE
AND
MINERAL TABLES.
3Y TEE SAME AUTHOR.
AN OUTLINE OF THE GEOLOGY OF CANADA,
BASED ON A SUBDIVISION OF THE PROVINCES
INTO NATURAL AREAS.
With six Sketch-maps and 86 figures of 'characteristic fossils.
BY E. J. CHAPMAN, PH.D., LL.D.
This work presents a synoptical view of the geology of the entire Dominion.
It is used as a book of reference in University College, Toronto ; in Queen's
College and University, Kingston ; and in the University of Halifax and
Science Department of Dalhousie College, Nova Scotia.
COPP, CLARK & CO,, 1877.
BLOWPIPE PRACTICE.
AN OUTLINE
OF
BLOWPIPE MANIPULATION AND ANALYSIS,
WITH ORIGINAL TABLES,
FOR THE
DETERMINATION OF ALL KNOWN MINERALS.
BY
B. J. CHAPMA
•
PH.D., LL.D.
PROFESSOR OF MINERALOGY AND GEOLOGY IN UNIVERSITY COLLEGE AND
PRACTICAL
TORONTO :
OOPP, CLARK & CO., 47 FRONT STREET EAST.
1880.
«' r '.,'
INTRODUCTORY NOTICE.
The title-page to this little work indicates succinctly the scope and
character of the book. The work comprises two distinct parts : an
introductory sketch of the use of the Blowpipe in qualitative mineral
examinations ; and a series of Tables, with chemical and crystallo-
graphic notes, for the practical determination of minerals, generally.
In the first portion of the work, the writer's aim has been to sys-
tematise and condense as far as possible : but, although confessedly
a mere outline of the subject, this introductory portion will not be
found altogether devoid of original matter. The sixth section, more
especially, contains a new and greatly simplified plan of BLOWPIPE
ANALYSIS, by which the general composition of an unknown sub-
stance may be determined in most cases very rapidly and with
comparatively little trouble. As a rule, the methods of Blowpipe
Analysis, hitherto published, are little more than Tables of Reac-
tions. They attempt no separation of electro-negative bodies from
bases, but mix up the two, very illogically ; and they exact the per-
formance of many unnecessary experiments, by which certain com-
ponents become detected over and over again, whilst others escape
detection, altogether, or are recognized only after much unnecessary
delay.* These defects are remedied very materially, it is thought,
in the method now proposed. The Determinative Tables, which
occupy the second and principal portion of the work, are also origi-
nal. In their arrangement, an attempt is made to place bodies of
related composition, only, under the same subdivision : so as to avoid,
wherever possible, the unnatural collocations so commonly seen in
Tables of this character. It will be evident, however, that without
greatly increasing the number of the Tables, complete success in this
respect is not always attainable. The Tables include, practically, all
* After the first part of this work was in tjpe and entirely struck off, the author received
from HRRR LANDAUER, of Brunswick, a copy of his " Systematischer Gang der Lothrohr-
Analyse." Herr Landauer's method entirely meets the above objections, and is without doubt
the most satisfactory plan of Blowpipe Analysis hitherto published. It has been subsequently
incorporated by its author into a little work on the Blowpipe, an English translation of which,
under the title of " Blowpipe Analysis," has recently appeared.
o \
VI BLOWPIPE PRACTICE.
known minerals ; but as many of these are rarely met with, or are
comparatively of little importance, an Explanatory Note, referring
only to species of ordinary occurrence, is attached to each Table. In
these Notes, more especially in those which relate to the concluding
Tables of the series, additional information is given respecting the
crystallization, spectroscopic reactions, and other distinctive charac-
ters of leading species. The spectroscope recommended for use, in
'these investigations, is a simple, direct- vision pocket-spectroscope,
such as can be carried very conveniently, with accompanying Bun-
sen-burner (the foot unscrewed), in a spare corner of the blowpipe
case.
SCHOOL OF PRACTICAL SCIENCE, TORONTO :
August 12th, 1880.
BRIEF SKETCH OF THE HISTORY OF THE BLOWPIPE.
The use of the Blowpipe, in the arts, dates from a very distant period — a
simple form of the instrument having been long employed, in the process of
soldering, by, jewellers and other workers in gold and silver. This employ-
ment must naturally have suggested its use to the alchemists ; and in the
curious collection of woodcuts known as the Liber mutus, in which an alchemist,
assisted by his wife, is depicted in the performance of various chemical opera-
tions, the use of the blowpipe is clearly indicated. The Liber mutus is of very
uncertain date, but it belongs, in all probability, to the beginning of the seven-
teenth century. The alchemist is here employed, it is true, not in the actual
examination of a substance by his blowpipe, but in the construction or sealing up
of a glass vessel. Nevertheless, the use of the instrument in the conversion of
calc spar into lime is pointed out by ERASMUS BARTHOLIN in his treatise on Ice-
land Spar, written in 1670 j and in the Ars vitraria experimentalis of KUNCKEL,
published in 1679, the blowpipe is recommended for use in the reduction, on
charcoal, of metal-holding bodies, the requisite blast being produced by a pair
of air-tight bags. In 1702, the celebrated alchemist JOHANN GEORG STAHL
distinctly refers to the reduction of lead and antimony, by the fusion of what
are now known as the oxides of these metals, on a piece of charcoal, by means
of a "soldering pipe" or tubulo ccementorio aurifabrorum. JOHANN ANDREAS
CRAMER, in his Elements docimasticce (1739) describes the use of the instrument
in the examination of small particles of metallic bodies, and suggests the use
of borax (long previously employed in soldering, and also by the alchemists in
crucible operations) for this purpose. He gives also a description of a mouth
blowpipe provided at its lower end with a cylindrical reservoir for the retention
of the moisture which condenses from the operator's breath.
INTRODUCTORY NOTICE. Vll
In Sweden, a few years later (1746), SWEN RINMAN published some details
on the examination of ferruginous tin-ore, and other minerals, by the blowpipe ;
and, in 1748, ANTON VON SWAB — usually, but erroneously, cited as the first
person by whom the blowpipe was used in its scientific applications — referred
to the use of the instrument in a paper on the occurrence of native antimony.
BERGMAN states that VON SWAB employed the blowpipe in 1738, but the date
of his first publication in which reference is made to its use is ten years later, as
pointed out by Dr. HERMANN KOPP in his valuable GescMchte der Chemie : 1844.
Up to this time, however, no general or systematic use of the blowpipe
appears to have been attempted ; but in 1758, AXEL FREDERIC CRONSTEDT,
who had previously employed the blowpipe in his researches on nickel (1751),
published anonymously at Stockholm his celebrated treatise on Mineralogy, in
which a chemical classification of minerals was first definitely essayed. In this
work, the pyrognostic characters of minerals, as determined by the blowpipe,
are brought prominently into notice ; and in addition to borax, the two general
reagents still in use, bicarbonate of soda (" sal sodce ") and microcosmic salt or
phosphor-salt (" salfusibile microcosmicum ") are employed as blowpipe fluxes.
To the English translation of Cronstedt's work published in 1770, GUSTAV VON
ENGESTROM appended a short but complete sketch of the use of the Blowpipe,
as then known ; and JOHN H YACINTH DE MAGELLAN added somewhat to this
sketch in the second (English) edition of the work, published in London in
1788. The plate which accompanies VON ENGESTROM'S essay, exhibits a
portable case of blowpipe apparatus, comprising, in addition to the blowpipe as
devised by Cronstedt, a hammer, anvil, magnet, silver spoon and other articles
(but none, of course, of platinum), with candle, charcoal, and three small
bottles for fluxes. This essay of VON ENGESTROM, attached to his translation
of Cronstedt's work, was translated into Swedish by RETZIUS in 1773 ; and in
the same year the Swedish chemist TORBERN BERGMAN published a memoir
on the blowpipe reactions of lime, magnesia, alumina, and silica ; whilst, in
1774, SCHEELE described the action of the blowpipe on manganese ores,
molybdenite, and other minerals. A few years later (1777) a complete treatise
in Latin on the use of the Blowpipe was drawn up by Bergman, and published,
soon after, under the editorship of Baron VON BORN, the metallurgist, at
Vienna (Commentatio de tuboferruminatorio, etc. : Vindobonce, 1779). A Swedish
translation, by HJELM, was issued at Stockholm in 1781.
In the preparation of this work, BERGMAN was very materially assisted by
JOHANN GOTTLIEB GAHN. The latter chemist subsequently carried out an
extended series of experiments with the blowpipe, and discovered various new
methods of research. BERZELIUS, to whom at an after period he communicated
personally his mode of operating, states that GAHN always carried his blowpipe
with him, even on his shortest journeys, and submitted to its action every new
or unknown substance that came in his way. In this manner he acquired
great skill in the use of the instrument. He published nothing, however, on
the subject ; but, finally, drew up at the instigation of BERZELIUS the short
sketch of the blowpipe and its applications contained in the latter's Larbok
i Kemie first issued in 1812. GAHN then undertook, in conjunction with
Vlll BLOWPIPE PRACTICE.
BERZELIUS, a complete blowpipe examination of all known minerals ; but his
death, in 1818, occurred almost at the commencement of this undertaking.
BERZELIUS therefore carried on the investigation alone ; and the results,
together with all the improvements and new processes introduced by Gahn
and by himself, were published at Stockholm under the title of Afhandling om
Blasrorets anvandende i Chemien, in 1820. This work has formed the basis of
almost all that has subsequently been published on the use of the Blowpipe in
qualitative researches, althou gh many new tests and methods of investigation
have been discovered since its date. At the death of its distinguished author
in 1853 it had entered its fourth edition, and had been translated into all the
leading European languages. An English translation (taken however from a
French version) by CHILDREN, appeared in 1821 ; and another by Whitney
(from the fourth German edition by HEINRICH HOSE) was published at Boston,
United States, in 1845.
A new era of blowpipe investigation commenced in 1827, when EDUARD
HARKORT, of Freiberg in Saxony, applied the instrument to the assaying or
quantitative examination of silver ores. HARKORT left Germany for Mexico,
and died there, soon after the publication of his essay on this subject (Probir-
kunst mit dem Lothrohre, Freiberg, 1827) ; but CARL FRIEDRICH PLATTNER,
to whom he had shewn his method of working, carried on this important
application of the blowpipe, and published elaborate memoirs on the assaying,
by this method, of gold, lead, copper, tin, nickel, and other metallic ores and
furnace products. His great work on the Blowpipe, bearing a similar title to
HARKORT'S earlier publication, appeared in 1835. It reached a third edition
in 1853 ; and since Plattner's death in 1858, two other editions (the last
in 1878) have been issued under the editorship of DR. THEODOR RICHTER,
Plattner's successor in the Freiberg Mining Academy. This work has been
translated into various languages. An American edition, by PROF. H. B.
CORNWALL, appeared in 1875.
Of late years, the use of the Blowpipe has been greatly extended ; and nu-
merous original memoirs on points relating to Blowpipe Practice and Analysis
have appeared from time to time in scientific journals. But the discussion of
these more modern investigations belongs properly to a future time. The
principal works published since the date of Plattner's treatise are mentioned
at page 21 of the present volume. To these must be added the Systematic
Course of Analysis of J. LANDAUER, referred to in the preceding note.
CONTENTS.
PART I.
§ 1. — THE BLOWPIPE : ITS STRUCTURE AND GENERAL USE 1
§ 2.— ACCESSORY APPLIANCES AND REAGENTS 4
§ 3. — STRUCTURAL PARTS AND CHEMICAL PROPERTIES OP FLAME 5
§ 4. — BLOWPIPE OPERATIONS :
I. The Fusion Trial 8
II. Treatment in closed Tube :
(i) Treatment in Flask or Bulb-Tube 9
(ii) Treatment in Closed Tube, proper 10
III. Roasting, and Treatment in Open Tube :
(i) Roasting on Charcoal, Porcelain, and other supports 11
(ii) Roasting and Sublimation in Open Tubes 11
IV. Treatment with Nitrate of Cobalt 12
V. Formation of Glasses on Platinum Wire, or on Charcoal :
(i) Details of Process ; Flaming, &c 12
(ii) Table of Borax Glasses 12
(iii) Phosphor-Salt Glasses 15
(iv) Glasses formed with Carb. Soda 15
VI. Reduction 15
VII. Cupellation 18
VIII. Fusion with Reagents in Platinum Spoon 20
§ 5. — BLOWPIPE REACTIONS :
(i) Non-metallic Bodies 22
1, Oxygen ; 2, Hydrogen ; 3, Sulphur ; 4, Selenium ; 5, Ni-
trogen ; 6, Chlorine ; 7, Bromine ; 8, Iodine ; 9, Fluorine ;
10, Phosphorus ; 11, Boron ; 12, Carbon; 13, Silicon.
(ii) Unoxidizable Metals 30
14, Platinum ; 15, Gold ; 16, Silver.
(iii) Volatilizabk Metals 32
17, Tellurium ; 18, Antimony ; 19, Arsenic ; 20, Osmium ;
21, Mercury ; 22, Bismuth ; 23, Lead ; 24, Thallium ; 25,
Cadmium ; 26, Zinc ; 27, Tin.
X CONTENTS.
§ 5. — BLOWPIPE REACTIONS — (Continued).
(iv) Flux-colouring Metals 40
28, Copper; 29, Nickel; 80, Cobalt; 31, Iron; 32, Tung-
stenum ; 33, Molybdenum ; 34, Manganese ; 35, Chromium ;
37, Uranium ; 38, Cerium ; 39, Titanium.
(v) Earth Metals 51
40, Tantalum (?) ; 41, Aluminium ; 42, Glucinum ; 43, Zir-
conium ; 44, Yttrium.
(vi) Alkaline-Earth Metals 54
45, Magnesium ; 46, Calcium ; 47, Strontium ; 48, Barium.
(vii) Alkali Metals 57
49, Lithium ; 50, Sodium ; 51, Potassium ; 52, Ammonium.
§ 6. — PLAN OF ANALYSIS.
(i) Determination of the Chemical Group to which a mineral sub-
stance belongs 60
(ii) Determination of the Base or Bases 63
APPENDIX — ORIGINAL CONTRIBUTIONS TO BLOWPIPE ANALYSIS.
1. Reaction of Manganese Salts on Baryta 71
2. Detection of Baryta in the presence of Strontia 71
3. Detection of Alkalies in the presence of Magnesia 72
4. Method of Distinguishing the red flame of Lithium from that of
Strontium 72
5. Method of Distinguishing FeO from Fe203 in Silicates and other
compounds 73
6. Detection of Lead in presence of Bismuth 74
7. Detection of Lithia in presence of Soda 74
8. Action of Baryta on Titanic Acid . . . 75
9. Detection of Manganese when present in minute quantity in
mineral bodies 75
10. The Coal Assay 76
11. Phosphorus in Iron Wire 81
12. Detection of minute traces of Copper in Iron Pyrites and other
bodies 82
13. Detection of Antimony in tube sublimates 83
14. Blowpipe reactions of Thallium 84
15. Opalescence of Silicates in Phosphor-salt 86
16. Reactions of Chromium and Manganese with Carbonate of Soda 87
17. Detection of Cadmium in presence of Zinc in blowpipe experiments 88
18. Solubility of Bismuth Oxide in Carbonate of Soda before the
blowpipe 88
19. Detection of Carbonates in Blowpipe Practice 89
20. Detection of Bromine in Blowpipe Experiments 90
21. Blowpipe reactions of Metallic Alloys 91
CONTENTS. XI
PART II.
ORIGINAL TABLES FOR THE DETERMINATION OF MINERALS.
Introduction : Explanation of Crystal Symbols, &c 95
Analytical Index to the Tables 99
Table I., 101; T. II., 103; T. III., 105; T. IV., 110
(N.B.— Cinnabar to be erased from this Table) ; T. V., 113 ;
T. VI., 115; T. VIL, 116; T. VIIL, 117; T. IX., 121 ;
T. X., 124; T. XL, 130; T. XII. , 132; T. XIIL, 135;
T. XIV., 143 ; T. XV., 149 ; T. XVI., 151 ; T. XVII., 163 ;
T. XVIIL, 171 ; T. XIX., 174 ; T. XX., 178 ; T. XXL, 181 ;
T. XXII., 182 ; T. XXIIL, 186 ; T. XXIV., 195 ; T. XXV.,
213 ; T. XXVI., 227 ; T. XXVIL, 256.
Index to Minerals described in Part II. . . 279
ADDITIONS AND CORRECTIONS.
PAGE 21. — The following works should be added to the list given in the
foot-note on this page : — Blowpipe Analysis by J. LANDAUER (English edition),
1880; "Clavis der Silicate" by Dr. LEOP. H. FISCHER, 1864.
P. 24, line 8 :— for "sulphates " read " most sulphates." See exceptions, in
Note to Table XVI., page 162.
P. 28, bottom line : for BO3, read BJ08.
P. 33, line 9: — after "the solution has a distinct reddish-purple colour,"
add, "and imparts a dark stain to metallic silver or lead test-paper, in the
manner of a sulphur or selenium compound."
P. 58, line 3 : — erase the comma after the word " various."
P. 59, at close of Potassium reactions, add, " If a piece of deep-blue glass,
however, be held between the spectroscope and the flame, the potassium line
will alone be visible."
P. 59, Foot-note. In reference to the statement in this note it may be
observed that the ash of tobacco shews the red K-line, in the spectroscope, by
simple immersion in the flame, but the Ca-lines only appear when the ash is
moistened with hydrochloric acid. If lithium be present (as in the Periqne
tobacco, &c. ) the crimson Li-line also comes out per se.
P. 61, under "Substances Indicated" (Expt. 1), add, "(2), Antimony,
Tellurium."
P. 66. Molybdenum, placed under Group 2 on this page, should be placed,
strictly, by itself, apart— as yielding infusible metallic grains and forming under
certain conditions a slight sublimate. But its true place (as stated in the
text) is in the Electro-Negative Table, and no error is likely to arise from the
arrangement adopted.
P. 105. To description of MARCASITE, add, "but sp. gr. slightly lower,
viz., 4 '7-4 *9;" and to description of PYRRHOTINE, add, "decomposed by
hydrochloric acid, with separation of sulphur and emission of sulphuretted
hydrogen odour.
P 110. Cancel CINNABAR. [The paragraph relating to this mineral slipped
in, here, by some oversight during the printing of the work.] See page 121,
its proper place.
P. 112, line 5 from bottom :— for "£K," read "— £R."
P. 119, foot-note :— for "HC acid," read "HC1 acid."
P. 163, first and second lines under APATITE, for "CaO," read "3 CaO."
P. 164, line 14 :— for D read C3.
P. 174: — Erase the heading "A1. — No WATER IN BULB-TUBE;" or, other-
wise, add "A2. — HYDROUS SPECIES," above line 8 from bottom.
P. 185, line 10 :— for 130° 33', read 113° 52'. The latter angle is that of the
more commonly occurring pyramid of Scheelite, over a middle edge.
In the Note to Table XIV., page 143, for Olivine read Olivenite.
AN OUTLINE
OP
BLOWPIPE PRACTICE,
AS APPLIED TO THE
QUALITATIVE EXAMINATION OF MINERAL BODIES.
§1.
THE BLOWPIPE— ITS STRUCTURE AND GENERAL USE.
The blowpipe, in its simplest form, is merely a narrow tube of
brass or other metal, bent round at one extremity, and terminating,
«it that end, in a point with a very fine orifice, Fig. 1. If we place
the pointed end of this instrument just within the flame of a lamp,
common candle, or gas-jet with nar-
row aperture, and then blow gently
down the tube, the flame will be
deflected to one side in the form of
a long narrow cone, and its heating
power will be greatly increased.
Many minerals, when held in the
form of a thin splinter at the point
of a flame thus acted upon, may be
melted with the greatest ease ; and
some are either wholly or partially
volatilized. Other minerals, on the contrary, remain unaltered.
Two or more substances, therefore, of similar appearance, may often be
separated and distinguished in a moment, by the aid of the blowpipe.
The blowpipe (in its scientific use) has, strictly, a three-fold appli-
cation. It may be employed, as just pointed out, to distinguish
minerals from one another : some of these being fusible, whilst others
are infusible j some attracting the magnet after exposure to the blow-
2
Fro. 1.
2 BLOWPIPE PRACTICE.
pipe, whilst others do not exhibit that reaction ; some imparting a
colour to the flame, others volatilizing, and so forth. Secondly, the
blowpipe may be employed to ascertain the general composition of a
mineral ; or to prove the presence or absence, in a given body, of some
particular substance, as silver, copper, lead, iron, cobalt, manganese,
sulphur, arsenic, antimony, and the like. Thirdly, it may be used
to determine, in certain special cases, the actual amount of a metallic
or other ingredient previously ascertained to be present in the sub-
stance under examination.
In using the blowpipe, the mouth is filled with air, and this is
forced gently but continuously down the tube by the compression of
the muscles of the cheeks and lips, breathing being carried on simul-
taneously by the nostrils. By a little practice, this operation becomes
exceedingly easy, especially in ordinary experiments, in which the
blast is rarely required to be kept up for more than twenty or thirty
seconds at a time. The beginner will find it advisable to restrict
himself at first to the production of a steady continuous flame, with-
out seeking to direct this on any object. Holding the blowpipe in
his right hand (with thumb and two outside fingers below, and the
index and middle finger above the tube), near the lower extremity,
he should let the inner part of his arm, between the wrist and the
elbow, rest against the edge of the table at which he operates. The
jet or point of the blowpipe is turned to the left, and inserted either
into or against the edge of the flame, according to the nature of the
operation, as explained below. After a few trials, when sufficient
skill to keep up a steady flame has been acquired, the point of the
flame may be directed upon a small splinter of some easily fusible
material, such as natrolite or lepidolite, held in a pair of forceps with
platinum tips.* Some little difficulty will probably be experienced
at first in keeping the test-fragment exactly at the flame's point ; but
this, arising partly from irregular blowing, and partly from the
beginner feeling constrained to look at the jet of the blowpipe and
the object simultaneously, is easily overcome by half-an-hour's practice.
A small cutting of metallic tin or copper supported on a piece of
well-burnt soft-wood charcoal can be examined in a similar manner.
* If forceps of this kind cannot be procured, a pair of steel forceps with fine points, such as
watchmakers use, may serve as a substitute. It will be advisable to twist some silk thread or
fine twine round the lower part of these, in order to protect the fingers. The points must be
kept clean by a file.
VARIOUS FORMS OF BLOWPIPE.
In these experiments, the beginner must be careful not to operate on
fragments of too large a bulk. The smaller the object submitted to
the flame, the more certain will be the results of the experiment.
In out-of-the-way places, the common form of blowpipe described
above is frequently the only kind that can be obtained. It answers
well enough for ordinary operations, but the moisture which collects
in it, by condensation from the vapour of the breath, is apt to be blown
into the flame. This inconvenience is remedied by the form of con-
struction shewn in the annexed figures, in which the instrument con-
sists of two principal portions, a main stem closed at one end, and a
short tube fitting into this, at right angles, near the closed extremity.
The short tube is also commonly provided with a separate jet or nozzle
of platinum. In this case, the jet can be cleaned by simple ignition
before the blowpipe-flame, or over the flame of the spirit-lamp. In
FIG. 2. FIG. 3. FIG. 4. FIG. 5.
the variety of blowpipe known as "Black's Blowpipe," Fig. 2, the main
tube is usually constructed of japanned tin-plate, and the instrument
is thus sold at a cheap rate. Mitscherlich's Blowpipe, Fig. 3, consist*
of three separate pieces which fit together, when not in use, as shewn
in Fig. 4. This renders it as portable as an ordinary pencil-case.
Fig. 5 represents Gahn's or Berzelius's Blowpipe, with a trumpet-
shaped mouth-piece of horn or ivory as devised by Plattner. This
mouth-piece is placed, of course, on the outside of the lips. It is
preferable to the ordinary mouth-piece, but is not readily used by the
4 BLOWPIPE PRACTICE.
beginner. In length, the blowpipe varies from about severf-and-a-half
to nine inches, according to the eyesight of the operator.
§2.
ACCESSORY APPLIANCES AND REAGENTS.
In addition to the blowpipe itself, and the forceps described above,
a few other instruments and appliances are required in blowpipe
operations.* The principal of these comprise : Some well-burnt, soft-
wood charcoal, and a thin narrow saw-blade to saw the charcoal into
rectangular blocks for convenient use ; a few pieces of platinum wire,
three or four inches in length, of about the thickness of thin twine,
to serve as a support in fusions with borax, &c. (see below) ; some
pieces of open glass-tubing of narrow diameter, and two or three
small glass flasks, or, in default, a narrow test-tube or two — the latter
used chiefly for the detection of water in minerals (see below) ; a
small hammer and anvil, or piece of hard steel, half-aii-inch thick,
polished on one of its faces ; a triangular file ; a bar or horse-shoe
magnet ; a pen-knife or small steel spatula ; a small agate pestle and
mortar; a small spirit-lamp; a platinum spoon; a small porcelain
capsule with handle ; and eight or ten turned wooden boxes or small
stoppered bottles to hold the blowpipe reagents. These latter are
employed for the greater part in the solid state, a condition which
adds much to their portability, and renders a small quantity sufficient
for a great number of experiments. The principal comprise : Car-
bonate of soda (abbreviated into carb. soda, in the following pages),
used largely for the reduction of metallic oxides and detection of sul-
phides and sulphates, manganese, &c., as explained below ; biborate
of soda, or borax, used principally for fusions on the platinum wire,
many substances communicating peculiar colours to the glass thus
formed ; and phosphate of soda and ammonia, commonly known as
microcosmic salt or phosphor-salt, used for the same purposes as borax,
and also for the detection of silicates and chlorides, as explained further
on. Reagents of less common use comprise : nitrate of cobalt (in solu-
tion); bisulphate of potash; black oxide of copper; chloride of barium;
metallic tin ; bone ash ; strips of yellow turmeric paper, and blue and
red litmus paper ; with a few other substances of special employment,
mentioned under § 5, below.
* Only the more necessary operations, instruments, &c., are here alluded to.
THE BLOWPIPE FLAME. 7
copper, <fec., impart a crimson, green, or other colour to the outer or
feebly luminous cone.
For the production of a reducing flame the
orifice of the blowpipe must not be too large.
The point is held just on the outside of the
flame, a little above the level of the burner
or wick, as shewn in Fig. 8. The flame, in
its deflected state, then retains the whole or
FIG. 8. a large portion of its yellow cone. The sub-
stance under treatment must be held within this (although towards
its pointed extremity), so as to be entirely excluded from the atmos-
phere ; whilst, at the same time, the temperature is raised sufficiently
high to promote reduction. As a general rule, bodies subjected to a
reducing treatment should be supported on charcoal.
For ordinary experiments, such as testing the relative fusibility, <fec.,
of minerals, the blowpipe may be used with the flame of a common
candle. The wick of the candle should be kept rather short (but not
so as to weaken the flame), and it should be turned slightly to the
left, or away from the point of the blowpipe, the stream of air being
blown along its surface. A lamp flame, or that of coal gas, however,
gives a higher temperature, and is in many respects preferable. The
upper part of the wick-holder (or jet, if gas be used) should be of a
rectangular or flattened oblong form, with its surface sloping towards
the left at a slight angle.* Either good oil, or, better, a mixture of
about 1 part of spirit of turpentine, or benzine, with 6 parts of strong
alcohol, may be used with the lamp. If the latter mixture be used,
equal volumes of the two ingredients must be first well shaken up
together, and then the rest of the alcohol added. If the wick crust
rapidly, the turpentine will be in excess, in which case another volume
of alcohol may be added to the mixture.
§4.
BLOWPIPE OPERATIONS.
The following are some of the more general operations required in
* The most convenient flame for blowpipe use is that of a small Bunsen burner, into which ia
.dropped a narrow tube (somewhat longer than the tube of the burner, and with sloped and
flattened upper surface), to cuj; off the supply of air and produce a luminous flame. This acces-
sory tube is of course to be removed when bulb-tubes or solutions are heated, or when a eub-
c.tance is ignited without the aid of the blowpipe.
8 BLOWPIPE PRACTICE.
blowpipe practice. The student should master them thoroughly,,
before attempting to employ the blowpipe in the examination or
analysis of minerals. A few additional operations of special employ-
ment are referred to in a subsequent section.
(1) The Fusion Trial. — In order to ascertain the relative fusibility
of a substance, we chip off a small particle, by the hammer or cutting
pliers, and expose it, either in the platinum-tipped forceps or on char-
coal, to the point of the blue flame (Fig. 7, above). If the substance
be easily reduced to metal, or if it contain arsenic, it must be sup-
ported on charcoal (in a small cavity made by the knife-point for its-
reception), as substances of this kind attack platinum.* In other
cases, a thin and sharply-pointed splinter may be taken up by the
forceps, and exposed for about half-a-minute to the action of the flame.
It ought not to exceed, in any case, the size of a small carraway seed —
and if smaller than this, so much the better. If fusible, its point or
edge (or on charcoal, the entire mass) will become rounded into a bead
or globule in the course of ten or twenty seconds. Difficultly fusible
substances become vitrified only on the surface, or rounded on th&
extreme edges ; whilst infusible bodies, though often changing colour,
or exhibiting other reactions, preserve the sharpness of their point and
edges intact.
The more characteristic phenomena exhibited by mineral bodies-
when exposed to this treatment, are enumerated in the following
table : t
(a) The test-fragment may "decrepitate" or fly to pieces. Example, most
specimens of galena. In this case, a larger fragment must be heated in a test-
tube over a small spirit-lamp, and after decrepitation has taken place, one of
the resulting fragments can be exposed to the blowpipe-flame as directed above.
Decrepitation may sometimes be prevented if the operator expose the test-
fragment cautiously and gradually to the full action of the flame.
(b) The test-fragment may change colour (with or without fusing) and become
attractable by a magnet. Example, carbonate of iron. This becomes first red,
then black, and attracts the magnet, but does not fuse. Iron pyrites, on the
other hand, becomes black and magnetic, but fuses also.
* In order to prevent any risk of injury to the platinum forceps, it is advisable (even if not
strictly necessary in all cases) to use charcoal as a support for bodies of a metallic aspect, as-
well as for those which exhibit a distinctly coloured streak or high specific gravity.
t Blowpipe operations, as described in this section, are not intended to serve as a course of
analysis. Merely a few examples, therefore,, ai» givea in. illustration, of their effects. For Plaa,
of Analysis,, see § 6.
OPERATIONS. 9
(cj The test-fragment may colour the flame. Thus, most copper and all
thallium compounds impart a rich green colour to the flame ; compounds in
which tellurium or antimony is present, also those containing baryta, and
many phosphates and borates, with molybdates and the mineral molybdenite,
colour the flame pale green ; sulphur, selenium, lead, arsenic, and chloride of
copper colour the flame blue of different degrees of intensity ; compounds con-
taining strontia and lithia impart a crimson colour to the flame ; some lime
compounds impart to it a pale red colour; soda compounds, a deep yellow
colour ; and potash compounds, a violet tint.
(d) The test-fragment may become caustic. Example, carbonate of lime.
The carbonic acid is burned off, and caustic line remains. This restores the
blue colour of reddened litmus paper.
(e) The test-fragment may take fire and burn. Example, native sulphur,
cinnabar, common bituminous coal, &c.
(/) The test-fragment may be volatilized or dissipated in fumes, either wholly
or partially, and with or without an accompanying odour. Thus, gray antimony
ore volatilizes with dense white fumes ; arsenical pyrites volatilizes in part, with
a strong odour of garlic ; common iron pyrites yields an odour of brimstone ;
and so forth. In many cases the volatilized matter becomes in great part
deposited in an oxidised condition on the charcoal. Antimonial minerals form
a white deposit or incrustation of this kind. Zinc compounds, a deposit which
is lemon-yellow whilst hot, and white when cold. Lead and bismuth are indi-
cated by sulphur-yellow or orange-yellow deposits. Cadmium by a reddish
brown incrustation.
(g) The test-fragment may fuse, either wholly, or only at the point and edges,
and the fusion may take place quietly, or with bubbling, and with or without a
previous "intumescence " or expansion of the fragment. Most of the so-called
zeolites, for example (minerals abundant in trap rocks), swell or curl up on
exposure to the blowpipe, and then fuse quietly ; but some, as prehnite, melt
with more or less bubbling.
(h) The test-fragment may remain unchanged. Example, quartz, and various
other infusible minerals.
(2) Treatment in the Flask or Bulb-Tube (The Water Test). — Minerals
are frequently subjected to a kind of distillatory process by ignition
in small glass tubes closed at one end. These tubes are of two general
kinds. One kind has the form of a small flask, and is commonly known
as a " bulb-tube." Where it cannot be procured, a small-sized test-
tube may supply its place. It is used principally in testing minerals
for water. Many minerals contain a considerable amount of water, or
the elements of water, in some unknown physical condition. Gypsum,
for example, yields nearly 21 per cent, of water. As the presence of
this substance is very easily ascertained, the water test is frequently
resorted to, in practice, for the formation of determinative groups, or
10
BLOWPIPE PRACTICE.
ssparation of hydrous from anhydrous minerals. The operation is
thus performed. The glass is first warmed gently over the flame of
a small spirit-lamp to ensure the absence of moisture, and is then set
aside for a few moments to cool. This effected, a piece of the sub-
stance under examination, of about the size of a small pea, is placed
in it, and ignited over the spirit-lamp — as
shewn in the annexed figure — the tube
being held in a slightly inclined position.
If water be present in the mineral, a thin
film, condensing rapidly into little drops,
will be deposited on the neck or upper part
of the tube. As soon as the moisture
begins to shew itself, the tube must be
brought into a more or less horizontal
position, otherwise a fracture may be
occasioned by the water flowing down and
coming in contact with the hot part of the
glass. The neutral, acid, or alkaline con-
dition of the water, can be determined by slips of blue and red litmus
paper. A mineral may also be examined for water, though less con-
veniently, by ignition before the blowpipe-flame in a piece of open
tubing, as shewn in Fig.
1 0. To prevent the tube
softening or melting, a
strip of platinum foil may
be folded around it where
the test-fragment rests.
Fl°- 10- The latter is pushed into
its place by a thin iron wire. The moisture condenses 011 each side
of the test-matter.
(3) Treatment in Closed Tubes, proper. — In addition to the flask or
bulb-tube, small pieces of narrow glass tubing — closed, and sometimes
drawn out to a point, at one extremity — are frequently used in the
examination of mineral bodies. The substance is ignited (either alone,
or mixed with thoroughly dry carb. soda or other flux) at the closed
end of the tube. After the insertion of the test-substance, the upper
part of the tube must be cleaned by a piece of soft paper twisted round
an iron wire, or by the feather end of a quill pen, &c. ; but this will
not be necessary if the substance be inserted by means of a narrow
OPERATIONS. 13
plunged into the flux, the adhering portion of the latter being then
fused into a glass. If a sufficient portion to fill the loop be not taken
up at first, the process must be repeated. With beginners, the fused
glass is often brownish or discoloured by smoke, but it may be rendered
clear and transparent by being kept in ignition for a few moments before
the extreme point of the flame, the carbonaceous matter becoming
oxidized and expelled by this treatment. When carbonate of soda is
used, a small portion of the flux must be moistened and kneaded in
the palm of the left hand, by a knife-point or a small spatula, into a
slightly cohering paste, which is placed on the loop of the wire, and
fused into a bead. Whilst hot, the soda bead is transparent, but it
becomes opaque on cooling. The portion of test-matter added to a
glass or bead, formed by these reagents, must be exceedingly small,
otherwise the glass may become so deeply coloured as to appear quite
black. In this case, the colour may be observed by pinching the bead
flat between a pair of forceps, before it has time to cool. It is always
advisable, however, in the first instance, to take up merely a minute
particle or two of the test-substance, and then to add more if no char-
acteristic reaction be obtained. The glass, in all cases, must be examined
first before an oxidating flame, and its colour observed both whilst
the flux is hot and when it has become cold ; and, secondly, it must
be kept for a somewhat longer interval in a good reducing flame
(Fig. 8), and its appearance noted as before.* With certain sub-
stances (lime, magnesia, &c.) the borax and phosphor-salt glasses
become milky and opaque when saturated, or when subjected to the
intermittent action of the flame — the latter being urged upon them
in short puffs, or the glass being moved slowly in and out of the
flame — a process technically known as Flaming.
The colours, &c., communicated to these glasses by the more com-
monly occurring constituent bodies, are shewn in the annexed tabular
view.
BORAX.
Violet or amethystine ........ Ma.gane.e . . . . j *%£% *
Violet-brown (whilst hot) . . ) XT- i i r\ j
Clear-brown (when cold). . . . | Nlckel .......... <***? and
Blue (very intense) .......... Cobalt .......... Blue (very deep).
* The colour of the glass ought not, of course, to be examined by the trantmitted light of the
lamp or candle flame. Strictly, it should be observed by daylight.
14
BLOWPIPE PRACTICE.
Colour of Bead after exposure
to an Oxidating Flame.
Green (whilst hot)
Blue or greenish-blue (cold) . .
Green or bluish-green
Green (dark)
Yellowish or reddish (hot) . .
Yellowish-green (when cold).
Yellow (whilst hot)
Greenish-yellow (cold) ,
Yellowish or reddish
Yellowish or reddish
Enamelled by flaming
Yellow (whilst hot)
Pale yellowish (cold)
Enamelled by flaming
Yellow (hot)
Colourless (cold)
Enamelled by flaming
Yellow (hot)
Colourless (cold)
Enamelled by flaming
Yellow (hot)
Colourless or yellowish (cold)
Grayish and opaque byflaming
Compounds of:
Colour of Bead after exposure
to a Reducing Flame.
SMore or less colourless whilst
hot ; brownish-red & opaque
on cooling.
Cobalt + Iron .... Green or bluish-green.
Copper-f Nickel ) Brownish-red, opaque, on
Copper+Iron. . \ cooling.
Chromium Emerald-green.
Vanadium . , . . j i^^y^^^'cdd),
Iron Bottle-green.
Uranium Green (black by flaming).
Cerium .
Titanium.
Tungstenum
> Molybdenum
Yellow or yellowish -red (hot)
Yellowish or colourless, and
' often opaline, when cold . .
Yellowish (hot)
Colourless (cold)
Opaque- white when saturated
Colourless(permanentlyclear)
Slowly dissolved
tfeeunder Phosphor-salt,below
r Lead
J Bismuth ...
1 Silver
I Antimony . .
Cadmium .
) Aluminium.
V Silicon
Tin
Colourless. When saturated,
opaque-white on cooling or
by flaming
r Tantalum . .
Zirconium . .
Glucinum . .
Yttrium, &c.
Thorium ....
Magnesium. .
Calcium ....
Strontium . .
Barium ....
Lithium ....
Natrium ....
I Kalium ....
( Colourless or yellowish.
( Opaque-white, if saturated.
Yellow or yellowish -brown.
Enamelled light-blue by flam*
See under Phosp. -salt, below.
( Yellow or yellowish-brown.
< Enamelled by flaming.
( £eeunderPhosphor-salt,below
f Brown or gray, semi-opaque,
j often with separation of black
I specks.
I Seeunder Phosphor-salt,below
( Gray and opaque on cooling ;
but after continued subjec-
tion to the flame, the glass
becomes clear : the reduced
metallic particles either col-
lecting together or Volatil-
izing.
Colourless — the reduced
metal being volatilized.
Colourless: permanently
clear. (Tin compounds dis*
solve in small quantity only.
On charcoal, they become
reduced to metal, especially
if a little carb. soda be added
I to the glass).
Colourless. When saturated,
opaque-white on cooling or
by flaming.
See REACTIONS, § 5.
OPERATIONS.
PHOSPHOR-SALT. * [>
The glasses produced by the fusion of constituent bodies with this
are for the greater part identical with those obtained by the use of
although somewhat less deeply coloured as a general rule. The princii
exceptions are the glasses formed in a reducing flame with compounds of
molybdenum, tungstenum, and titanium, respectively. The molybfteajiiff *
glass presents, when cold, a fine green colour, and the tungstenum glass
becomes greenish-blue. If the latter contain iron, the colour of the glass ia
changed to blood-red or brownish-red. Titanium in the presence of iron gives
a similar reaction ; but when free from iron, the glass is yellow whilst hot, and
violet- coloured when cold. Phosphor-salt is an important reagent for the
detection of silica in silicates, as the silica remains for the greater part undis-
aolved in the glass, in the form of a translucent flocculent mass, technically
known as a "silica skeleton," the associated constituents being gradually
taken up by the flux. A small amount of silica is also generally dissolved,
but this is precipitated as the bead cools, rendering it semi-transparent or
opaline. Phosphor-salt is likewise employed for the detection of chlorides, &c.
(See. under REACTIONS, § 5. ) In other respects, it is especially adapted for fusions
on charcoal, as it does not spread out like borax, but forms a globule on the
support.
CARBONATE OF SODA.
This reagent is principally used to promote the reduction of oxidized and
other bodies to the metallic state, as explained below, under that process.
It is also of very frequent employment as a test for sulphur in sulphides and
oxidized bodies. (See under REACTIONS, § 5.) It is rarely used, on the other
hand, for the formation of glasses on platinum wire, except as a test for the
presence of manganese ; although, when employed in this manner, it serves to
distinguish salts of the alkalies, and tho^ of strontia and baryta, from all
other salts : the alkalies, with baryta and strontia, dissolving completely and
rapidly in the bead, whereas lime, magnesia, alumina, and other bases, remain
unattacked. Manganese compounds form by oxidizing fusion with this reagent
a green glass, which becomes blue or bluish-green and opaque on cooling. A
very minute amount of manganese may be thus detected. The delicacy of the
test is increased by the addition of a small quantity of nitre, as this promotes
oxidation ; and if the substance contain much lime, magnesia, iron oxides, or
other bodies more or less insoluble in carb. soda, it is advisable to add a little
borax to the test-mixture. The blue or bluish-green bead thus produced, is
technically known as a "turquoise enamel." Chromium compounds produce
a somewhat similar reaction ; but if the bead be saturated with silica or boracic
acid, it will remain green in the latter case ; while if the green colour result
from the presence of manganese, a violet or amethystine glass will be obtained.
Some other applications of carbonate of soda as a blowpipe reagent will be
found under the head of REACTIONS, § 5.
(8) Reduction. — This term denotes the process by which an oxidized
or other compound is converted into the metallic state. Some com-
16 BLOWPIPE PRACTICE.
pounds become reduced by simple ignition • others require for their
reduction the addition of certain reagents ; and some, again, resist
reduction altogether. The reduced metal is in some cases so highly
volatile that it cannot be obtained except by a kind of distillatory
process. In other cases, one or more fusible globules, or a number
of minute infusible grains, are obtained in blowpipe operations.
Reducible metals may be thus distributed into three groups, as shewn
(with omission of a few metals of rare occurrence) in the annexed
table:
A. Yielding metallic globules. — Gold, silver, copper, tin, lead, bismuth*
antimony.
B. Yielding infusible metallic grains. — Platinum, iron, nickel, cobalt, molyb*
denum, tungstenum.
C. Yielding metallic vapours only, when treated on charcoal. — Mercury, arsenic,
cadmium, zinc.
A metal of the first group may be obtained, unless present in very
small quantity, by a simple fusion of the previously roasted test-sub-
stance, with some carbonate of soda, on charcoal, in a good reducing
flame (Fig. 8, above). In ordinary cases, metallic globules are rapidly
produced by this treatment. By a little management the globules
may be brought together, so as to form a single large globule. This
must be tested on the anvil as regards its relative malleability,* <fec.
Gold, silver, copper, tin and lead are malleable ; bismuth and anti-
mony, more or less brittle. Gold and silver (if pure) retain a bright
surface after subjection to an oxidating flame. Copper becomes
covered with a black film, and tin with a white crust. Lead and
bismuth volatilize more or less readily, and deposit on the charcoal
a yellow coating of oxide. Antimony is rapidly volatilized with de-
position of a dense white incrustation on the charcoal. It is not, of
course, always necessary to subject the test-substance to a previous
roasting (Operation 4, above), but it is always safer to do so. Sul-
phur in most, and arsenic in all cases, must be driven off by this
preliminary treatment before the actual process of reduction is
attempted.
When the metal to be reduced belongs to the second group, or if
*To test the relative malleability of a metallic globule as obtained by the blowpipe, the
globule must be placed on a small steel anvil, and a strip of thin paper (held down by the fore*
finger and thumb of the left hand) being placed over it to prevent dispersion, it is struck once
or twice by a light hammer. Thus treated, malleable globules become flattened into discs,
whilst brittle globules break into powder
OPERATIONS. 17
the amount of a fusible metal in the test- substance be less than 4 or
5 per cent., the operation is performed as follows : A small portion
of the substance in powder — subjected previously to the roasting pro-
cess, if it contain sulphur or arsenic — is mixed with 3 or 4 volumes
of carbonate of soda (or neutral oxalate of potash, or a mixture of
about equal parts of carb. soda and cyanide of potassium — -the latter,
it must be remembered, a highly poisonous substance), and the mix-
ture is exposed on charcoal to a good reducing flame, until all the
alkaline salt has become absorbed. More flux is then added, and
the operation is repeated until the whole or the greater part of the
test-matter is also absorbed. This effected, the charcoal, where the
assay rested, is removed by a sharp knife-point, and carefully ground
to powder in a small agate mortar or porcelain capsule, whilst a fine
stream of water is projected upon it from time to time, until all the
carbonaceous and other non-metallic particles are gradually washed
away. For this purpose, the mortar or capsule may be placed in the
centre of an ordinary plate ; and if the operator be not provided with
a chemical washing-bottle, he may use a small syringe, or, in place of
this, a simple piece of glass tubing, five or six inches in length and
about the fourth of an inch in diameter, drawn out at one end to a
point. This is filled by suction, and the water is expelled, with the
necessary force, by blowing down the tube. The metallic grains or
spangles obtained by this process must be examined by the magnet.
Those of iron, nickel and cobalt are magnetic. Sometimes, however,,
when but a trace or very small percentage of reducible metal is con-
tained in the test-substance, its presence is only indicated by a few
metallic streaks on the sides and bottom of the mortar. Metallic
markings of this kind can be removed by a piece of pumice.
Metallic compounds referable to the third group, yield no metal on
charcoal, or by other treatment in open contact with the atmosphere.
The presence of arsenic, however, is easily made known by the garlic-
like odour evolved during fusion with reducing agents (or alone) on
charcoal. Cadmium and zinc may also be recognized by the oxidized
sublimates which they deposit on the charcoal. The cadmium sub-
limate is reddish-brown ; the zinc sublimate, lemon-yellow and phos-
phorescent whilst hot, and white when cold. Mercury forms no
incrustation on charcoal ; but its presence in any compound may be
determined by reduction with carbonate of soda or iron-filings in a
3
18 BLOWPIPE PRACTICE.
glass tube of narrow diameter. A small test-tube or piece of glass
tubing closed at one end before the blowpipe, may be used for the
experiment. The test-substance, in powder, mixed with 3 or 4 vols.
of perfectly dry carb. soda, is inserted into the tube by means of a
narrow strip of glazed writing-paper bent into the form of a trough ,
so as to prevent the sides of the glass from being soiled, and the
mixture is strongly ignited by the spirit-lamp or by the blowpipe-
flame. If mercury be present, a gray metallic sublimate will be
formed near the upper part of the tube. By friction with an iron
wire, or the narrow end of a quill -pen, &c., the sublimate may be
brought into the form of fluid globules, which can be poured out of
the tube, and are then easily recognized as metallic mercury.
(9) Cupellation. — Gold and silver are separated by this process from
other metals. The test-metal is fused wdth several times its weight
of pure lead. The button, thus obtained, is exposed to an oxidating
fusion on a porous support of bone ash, known as a cupel. The lead
and other so-called base metals become oxidized by this treatment, and
•are partly volatilized, and partly absorbed by the bone ash, a globule
of gold or silver (or the two combined) being finally left on the sur-
face of the cupel. For blowpipe operations, cupels are generally
made by pressing a small quantity of dry bone ash into a circular
iron mould, the latter being fixed, when presented to the flame, in a
special support, consisting essentially of a wooden foot and pillar
supporting a wire stem, with three or four short cross-wires at the
top, between which the cupel-mould rests. Instruments of this kind
cannot be obtained in remote places, but the process may be performed
equally well by pressing some dry bone ash into a suitable cavity
fashioned at the extremity of a cylindrical piece of pumice or well-
baked clay, or even charcoal. The smooth end of the agate pestle,
or a glass button cemented to a cork, or the rounded end of a glass
stopper, may be used for this purpose. The cupel, thus formed, must
then be exposed for a few moments to the point of the blowpipe-flame^
so as to render the bone ash perfectly dry ; and if its surface become
blistered or be in any way affected by this drying process, it must be
rendered smooth again by pressure with the pestle. The substance
to be cupelled must be in the metallic state ; if not in this condition,
therefore, it must first be subjected to the reducing operation described
above. The piece of test-metal, which may weigh about a couple of
OPERATIONS. 19
grains (or from 100 to 150 milligrammes) is wrapped in a piece of
pure lead-foil of at least four times its weight, and the whole is
exposed, on the surface of the cupel, to the extreme point of a clear
oxidating flame. If the substance consist of argentiferous lead, as
obtained from galena, &c., the addition of the lead-foil is of course
unnecessary,* As soon as fusion takes place, the cupel must be
moved somewhat farther from the flame, so as to allow merely the
outer envelope of the latter, or the warm air which surrounds this,
to play over the surface of the globule. By this treatment, the lead
will become gradually converted into a fusible and crystalline slag.
When this collects in large quantity, the position of the cupel must
be slightly altered, so as to cause the globule to flow towards its edge,
the surface of the lead being thus kept free for continued oxidation.
When the globule becomes reduced to about a fourth or fifth of its
original bulk, the process is discontinued, and the cupel is set aside to
cool. This is the first or concentration stage of the process. Another
cupel is then prepared and dried ; and the concentrated globule — after
careful separation from the slag in which it is imbedded — is placed
on this new cupel, and again subjected to the oxidizing influence of
the flame. During this second part of the process, the flame is made
rather to play on the surface of the cupel around the lead button than
on the button itself, a complete absorption of the oxidized lead being
thus effected. The flame should be sharp and finely-pointed, and
urged down on the cupel at an angle of forty or forty-five degrees.
Finally, if the test-metal contain gold or silver, a sudden flash or
gleam will be emitted at the close of the operation, and a minute
globule of one (or both) of these metals will be left on the surface of
the bone ash. By concentrating several portions of a test substance,
melting the concentrated globules together, again concentrating, and
finally completing the cupellation, as small an amount as half an ounce
* In reducing galena, with a view to test the lead for silver by cupellation, the reduction
may be conveniently performed as follows : A small portion of the galena, crushed to powder,
is mixed with about twice its volume of carb. soda, to which a little borax has been added.
This is made into a paste by the moistened knife-blade, and a short piece of thin iron wire is
stuck through it, and the whole is then placed in a charcoal cavity, and exposed for a couple
of minutes to the action of a reducing flame. By a little management, the minute globules of
lead which first result can easily be made to run into a single globule. The iron serves to take
up the sulphur from the galena. When the fused mass is sufficiently cool, it is cut out by a
sharp knife-point, and flattened (under a strip of paper) on the anvil. The disc of reduced
lead, thus separated, is then ready for cupellation. See also, under silver, § 5.
20 BLOWPIPE PRACTICE.
of gold or silver in a ton of ore — or in round numbers, about one
part in sixty thousand — may be readily detected by the blowpipe.*
During cupellation, the process sometimes becomes suddenly arrested.
This may arise from the temperature being too low, in which case the
point of the blue flame must be brought for an instant on the surface
of the globule, until complete fusion again ensue. Or, the hindrance
may arise from the bone ash becoming saturated, when a fresh cupel
must be taken. Or, it may be occasioned, especially if much copper or
nickel be present, by an insufficient quantity of lead. In this latter
case, a piece of pure lead must be placed in contact with the globule,
and the two fused together ; the cupel being then moved backward
from the flame, and the oxidating process again established.
(10) Fusion with Reagents in Platinum Spoon. — This operation
is only required in certain special cases, as in the examination of a
substance suspected to be a tungstate or molybdate, or in searching
for the presence of titanic acid, &c. The substance, in fine powder,
is mixed with three or four parts of the reagent (carb. soda, or bisul-
phate of potash, &c.), and the mixture, in successive portions, is fused
in a small platinum spoon. As a rule, the flame may be made to
impinge upon the bottom of the spoon ; and the operation is termi-
nated when bubbles cease to be given off and the mixture enters into
FIG. 12.
quiet fusion. During the operation the spoon is held in the spring-
forceps (Fig. 12), the points of which remain in close contact when
the sides are not subjected to pressure. The fusion accomplished, the
spoon is dropped, bottom upwards, into
a small porcelain capsule (Fig. 13) pro-
vided with a handle. Some distilled
water is then added and brought to the
boiling point over the spirit-lamp. The
Fl°- 13- fused mass quickly separates from the
spoon, and it can then be crushed to powder and again warmed until
* A cupellation bead may appear from its pure white colour to consist of silver only, and
may yet contain a notable amount of gold. A white bead, therefore, should be flattened into
a disc, and fused with some bisulphate of potash in a small platinum spoon. By this treatment
the silver is removed from the surface of the disc, and the latter, if gold be present, assumes a
yellow colour. If the metal be again fused into a globule, the white colour is restored.
REACTIONS. 21
solution, or partial solution, takes place. When the undissolved mat-
ters have settled, the clear supernatant liquid is decanted carefully
into another capsule (or into a test-tube) for further treatment. (See
Experiments 7 and 8, in § 6, beyond.)
§5.
BLOWPIPE REACTIONS.
In this section, the leading reactions of the more important
elementary bodies and chemical groups are passed rapidly under
review. Bodies of exceptional occurrence as mineral components —
or such of these, at least, as cannot be properly detected by the blow-
pipe— are omitted from consideration.* The other elementary sub-
stances are taken in the order shewn in the following index :
I. Non-metallic Bodies.— I, Oxygen; 2, Hydrogen; 3, Sulphur;
4, Selenium ; 5, Nitrogen ; 6, Chlorine ; 7, Bromine ; 8, Iodine ; 9,
Fluorine; 10, Phosphorus; 11, Boron; 12, Carbon; 13, Silicon.
II. Unoxidizable Metals. — 14, Platinum; 15, Gold; 16, Silver.
III. Volatilizable Metals. — 17, Tellurium; 18, Antimony; 19,
Arsenic ; 20, Osmium ; 21, Mercury ; 22, Bismuth ; 23, Lead ; 24,
Thallium; 25, Cadmium; 26, Zinc; 27, Tin.
IV. Flux-colouring Metals.— 2%, Copper; 29, Nickel; 30, Cobalt;
31, Iron: 32, Tungstenum ; 33, Molybdenum; 34, Manganese; 35,
Chromium; 36, Vanadium; 37, Uranium; 38, Cerium; 39, Titanium.
V. "Earth" Metals. — (40, Tantalum?); 41, Aluminium; 42,
Glucinum ; 43, Zirconium ; 44, Yttrium.
* For full details respecting the blowpipe reactions of inorganic bodies generally, the following
works may be especially consulted: 1. The old work by Berzelius, "Die Anwendung des
Lothrohrs," etc. ; translation of the 4th edition, by J. D. Whitney : Boston, 1845. 2. " Hand-
buch der Analytischen Chemie," von Heinrich Rose, 6th edition, by R. Finkener : Leipsig,
1871. 3. Plattner's " Probirkunst mit dem Lothrobr," 5th edition, by Richter, 1878. American
translation of 4th edition, by H. B. Cornwall : New York, 1875. 4. " Untersuchungen mit dem
Lothrohr," by Dr. H. Hartmann : Leipsig, 1862. 5. " Lothrohr-Tabellen," by Dr. J. Hirsch-
wald : Leipsig und Heidelberg, 1875. 6, "Manual of Determinative Mineralogy and Blowpipe
Analysis," by George J. Brush : 2nd edition, 1878. 7. " Leitfaden bei qual. und quan. Loth-
rohr-Untersuchuagen," von Bruno Kerl, 2nd edition, Clausthal, 1877. For the determination
of minerals, &c., the far-renowned " Tabellen" of Von Kobell (in addition to the work of Prof.
Brush, essentially constructed on that of Von Kobell, although with much amplification and
addition of new matter) may be especially consulted. The " Anleituiig zum Bestimmen der
Mineralien," of Dr. Fuchs, is also a very serviceable little book ; and some useful tables will
be found at the end of E> S, Dana's excellent "Text Book of Mineralogy."
BLOWPIPE PRACTICE.
VI. Alkaline-Earth Metals. — 45, Magnesium ; 46, Calcium : 47,
Strontium; 48, Barium.
VII. Alkali Metals.— 49, Lithium; 50, Sodium; 51, Kalium ;
52, Ammonium.
I. — NON-METALLIC BODIES.
(1) Oxygen. — Although this element occurs so abundantly as a
constituent of mineral bodies, its presence, as a rule, can only be
inferred by negative evidence. If a substance be neither one of the
few known simple bodies of natural occurrence, as gold, carbon, &c.,
nor a sulphide, selenide, arsenide, chloride, &c., it may be regarded
with tolerable certainty as an oxidized body. And if, farther, its
examination shew that it is not an oxygen-salt, i.e., a sulphate, car-
bonate, silicate, or the like, we can then only infer that it must be a
simple oxide, either electro-negative or basic in its characters.
All non-oxidized bodies attackable by nitric acid, decompose the
latter in taking oxygen from it, and thus cause the evolution of ruddy
nitrous fumes; but this decomposition is also effected by certain
oxides in passing into a higher state of oxidation, as by Cu2O, for
example.
Some few bodies, as binoxide of manganese, nitrates, chlorates,
bichromates, &c., give off oxygen on strong ignition. If these be
ignited (in not too small a quantity) in a test-tube containing at its.
upper part a charred and feebly glowing match-stem, the latter, as
the evolved oxygen reaches it, will glow more vividly. These bodies,
also, if fused with borax or phosphor-salt, dissolve with strong ebulli-
tion ; but carbonates produce the same reaction.
(2) Hydrogen. — -This element, apart from its occurrence in bitumen
and other hydro-carbonaceous substances, is only present in oxidized
minerals. From these, it is evolved, with oxygen, in the form of
water, during the ignition of the substance. (See Operation 2, page 9.)
(3) Sulphur. — Occurs in the free state, as "native sulphur;" also
combined with metals in sulphides and sulphur-salts ; and in combina-
tion with oxygen, as SO3, in the large group of sulphates. Native
sulphur is readily inflammable, burning with blue flame, and vola-
tilizing (with the well known odour of burning brimstone) in the;
REACTIONS.
\ e> - /^. /. <vx>
'
form of sulphurous acid SO2. Metallic sulphides and sulphur-salts
(especially if previously reduced to powder and moistenetl^intrf^ ^
paste), when roasted in an open tube of not too narroV^^eter, ^ K
give off the same compound (SO2), easily recognized by its oddtH^aB&l.
by its action on a slip of moistened litmus paper placed at the top of
the tube, the paper becoming reddened by the acid fumes. In very
narrow (as in closed) tubes, part of the evolved sulphur may escape
oxidation, and may deposit itself 011 the inside of the tube near the
test-substance. The sublimate, thus formed, is distinctly red whilst
hot, and yellow on cooling. From many arsenical and antimonial
sulphides also, a coloured sublimate of this kind, but consisting of
As2S3, or 2Sb2S3 -f Sb203, &c., may be deposited in narrow tubes,
especially if the tube be held more or less horizontally.
Sulphides of all kinds, if fused on charcoal with carb. soda (or
better, with carb. soda mixed with a little borax) readily form an
alkaline sulphide or " hepar." This smells, when moistened, more or
less strongly of sulphuretted hydrogen, and imparts a dark stain to
silver, or to paper previously steeped in a solution of lead acetate.
A glazed visiting card may be used as a substitute for the latter. The
stain is removed from the silver surface by friction with moistened
boneash.
Sulphates fused with carb. soda and a little borax (the borax in the
case of earthy sulphates greatly assisting the solvent power of the flux)
produce the same reaction. This reaction is of course produced
also by sulphites (which do not occur, however, as minerals), and
by bodies which contain selenium in any form. Sulphites, treated
with hydrochloric acid, evolve sulphurous acid, easily recognized by
its smell and its action on litmus paper ; and, in acid solutions, they
yield no precipitate with chloride of barium. Sulphates, on the other
hand, emit no odour of SO2 when treated with hydrochloric acid ; and
chloride of barium produces an insoluble precipitate in their acid
or other solutions. Bodies containing selenium, are distinguished
from sulphur compounds by the strong odour, resembling that of
" cabbage- water," which they evolve on ignition.
The efficacy of the sulphur-test is imperilled however by two
causes : (1), the difficulty, in many places, of procuring carbonate of
soda perfectly free from traces of sulphates ; and (2), the very fre-
quent presence of sulphur in the flame, where gas is used in blow--
24 BLOWPIPE PRACTICE. *
pipe operations. The first defect may be remedied (if the carb.
soda, employed alone, produce the reaction) by substituting, as pro-
posed by Plattner, oxalate of potash for the test, as that salt is
generally pure and free from sulphates; and the flame of a candle,
or an oil or spirit-flame, may be used in this experiment, when the
gas flame is found by trial with pure soda or oxalate of potash to
give the reaction.
Sulphides of natural occurrence are distinguished from sulphates,
by emitting sulphurous acid (or, strictly, by emitting sulphur vapour
which combines with atmospheric oxygen and forms sulphurous acid)
on .ignition; although in the case of certain sulphides (blende,
molybdenite, <fec.) a strong reaction is only produced by the ignition
of the substance in powder. Most natural sulphides, also, present a
metallic aspect, or otherwise are highly inflammable (orpiment,
cinnabar, &c.), or yield a strongly-coloured streak. Light-coloured
varieties of zinc blende are the only exception. On the other hand,
no sulphate possesses a metallic aspect ; and, in all, the streak is
either colourless or very lightly tinted.
(•1) Selenium. — Met with only in a few minerals of very rare
occurrence. In these, its presence is revealed by the formation of a
"hepar" with carb. soda, and simultaneous emission of strongly-
smelling fumes, the odour resembling that of decaying vegetable
matters or " cabbage water." In volatilizing, selenium, like sulphur,
burns with a blue flame.
(5) Nitrogen. — Found only, as regards minerals proper, in an
oxidized condition (Ni2O5) in nitrates. These are soluble or (as
regards certain metallic nitrates) sub-soluble in water; and they
deflagrate when ignited on charcoal or in contact with other carbo-
naceous bodies. Heated with a few drops of sulphuric acid (or fused
with bisulphate of potash) in a test-tube, nitrates evolve, also, ruddy
fumes of nitrous acid ; and many nitrates, moistened with sulphuric
acid, impart a dull green coloration to the flame-border.
(6) Chlorine. — Occurs, among minerals, in combination with
various bases, forming the group of chlorides. In these, its presence
is very easily recognized by the bright azure-blue coloration of the
REACTIONS. 25
flame-border which originates during the fusion of a chloride with
a bead of phosphor-salt coloured by oxide of copper. The fusion may
be performed on a loop of platinum wire, the phosphor-salt being first
fused with some black oxide of copper into a somewhat deeply
coloured glass, and the test-substance, in the form of powder, being
then added. Or the fusion may be made on a thin copper-wire with
phosphor-salt alone, the end of the wire being cut off after each
experiment. By this treatment, chlorides become decomposed, and
chloride of copper is formed. The latter compound rapidly volatilizes*
and imparts a remarkably vivid bright-blue colour to the flame. The
coloration soon passes, but can, of course, be renewed by the, addition
of fresh test-matter to the bead. Care must be taken to use pure
phosphor-salt, as that reagent, unless carefully made, is frequently
found to contain traces of chloride of sodium.
Oxidized chlorine-compounds do not occur as minerals, but it may
be stated that chlorates produce the same flame-reaction as chlorides,
when fused with phosphor-salt and copper oxide. All chlorates,
Jiowever, detonate like nitrates, only more violently, when ignited in
contact with carbonaceous bodies ; and they turn yellow, decrepitate,
and emit greenish fumes when warmed with a few drops of sulphuric
acid (or fused with bisulphate of potash) in a test-tube. The fumes
smell strongly of chlorine, and bleach moistened litmus paper.
Chlorides, when thus treated with sulphuric acid, effervesce and give
off white fumes of hydrochloric acid.
(7) Bromine. — Only known, among minerals, in some rare silver
bromides. Its blowpipe reactions closely resemble those of chlorine,
but the flame-coloration of bromide of copper is a bright blue with
green streaks and edges. A small sharply-pointed flame is required
to shew the reaction properly ; and care must be taken not to add
the test-matter to the cupreous phosphor-salt bead until all traces of
the green coloration, arising from the oxide of copper, have disap-
peared. Heated in a test-tube with sulphuric acid (or fused with large
excess of bisulphate of potash) bromides yield brownish or yellowish-
red, strongly smelling vapours of bromine. Bromates produce the
same reaction, but this is accompanied by sharp decrepitation ; and
when fused on charcoal they detonate more or less violently. (See
Appendix, No. 20).
26
BLOWPIPE PRACTICE.
(8) Iodine. — In nature, occurs only in one or two rare minerals,
compounds of iodine and silver, or iodine, silver, and mercury. In
these, as well as in all artificial iodides, its presence may be recognized
by the vivid green coloration imparted to the flame during fusion
with a cupreous phosphor-salt bead. The test-matter must not be
added to the bead until the copper oxide is completely dissolved in
the latter, and all traces of green (communicated by the CuO) have
disappeared from the flame. Iodides, also, when warmed with a
few drops of sulphuric acid (or fused with excess of bisulphate of
potash) in a test-tube, evolve strongly smelling violet-coloured
vapours, which impart a deep blue stain to matters containing
starch. A strip of moistened tape or starched cotton may be held
at the top of the tube. lodates exhibit the same reactions, but
deflagrate when ignited with carbonaceous bodies. (See Appendix,
No. 20).
(9) Fluorine. — This element, as an essential component of minerals,
occurs in combination with calcium and other bases, forming the *
various fluorides. It is also largely present in topaz, probably in
combination with silicon and aluminium ; and it occurs, though in
smaller proportion, in chondrodite, and as an accidental or inessential
component in many other silicates. Its presence is revealed most
readily, by warming the substance, in powder, with a few drops of
sulphuric acid (or fusing it with bisulphate of potash) in a test-tube,
when stifling fumes, which strongly corrode the inside of the glass,
are given off. Or, the trial may be made in a platinum crucible
covered with a glass plate : on washing the test-tube or glass, and
drying it, the corrosion is rendered visible. When fluorine is present
in very small quantity in a substance, it is generally driven off the
more readily, often by the mere ignition of the substance (either
alone, or with previously fused phosphor-salt) at one end of an open
narrow tube — the flame being directed into the tube, so as to decom-
pose the test-matter and drive the expelled gases before it. A slip
of moistened Brazil-wood paper, placed at the mouth of the tube, is
rendered yellow. Many silicates which contain only traces of fluorine
lose their polish when strongly ignited, in the form of a small splinter,
per se.
REACTIONS. 27
(10) Phosphorus. — Occurs, in minerals, in an oxidized condition
only, i.e., as phosphoric acid (or anhydride) in the group of phosphates.*
As first pointed out by Fuchs, these bodies, when moistened with
sulphuric acid, impart a green coloration to the flame-border, and
many produce this reaction per se. A closely similar coloration,
however, is communicated to the flame by borates (when moistened
with sulphuric acid), as well as by bodies containing barium, copper,
&c. It only serves, therefore, as a probable indication of the presence
of phosphoric acid. The readiest and most certain method of detect-
* It is assumed to be in this condition simply because phosphates give the known reactions
of phosphoric acid or phosphoric anhydride, although these reactions may, of course, be
modified to some extent by the presence of other bodies. In like manner, when iron is present
in an oxidized body, we assume that it is present in the condition of FeO if the substance give
the known reactions of that compound, and increase in weight on ignition ; and that it is
present as Fe203 if the reactions of sesquioxide of iron be given by the substance. As to the
actual conditions, either physical or chemical, of bodies in combination, we know absolutely
nothing, but we have a certain knowledge of the secondary components of most bodies. We
are able to examine these components apart, and to form more complex bodies by their union.
Thus, from a piece of limestone or calcite we can obtain two well known compounds, lime and
carbonic acid (or carbonic anhydride) ; and with these compounds we can readily produce
limestone or its equivalent. Hence, the simplest and most practically useful way of stating,
either verbally or by symbols, the composition of limestone and other mineral bodies, is surely
that which makes known to us at once the components into which the body readily splits up
or decomposes, or which characterize it directly by their reactions. This method, therefore, is
adhered to in the present handbook. It may be urged that a formula of the kind represented
by CaO, CO2 asserts too much, and that consequently the more modern Ca CO3 is preferable.
But rightly considered, the old formulae need not be assumed to make any assertions regarding
the actual condition of bodies in combination, but only to indicate clearly the well known
simple compounds into which (in the great majority of cases) substances may be more or less
readily decomposed, and the reactions which substances exhibit. As a strict matter of fact,
moreover, the new formulae are not free from assertion. They carry upon their face, at least,
a seeming assertion that the elementary bodies in compounds are present in an absolutely free,
separate and independent state; or that unknown problematical compounds, as CO 3, SiO 4,
SiO 5, SiO 6, etc., etc., are present in the substances to which theso formulae refer. To take
another illustration. A student has two minerals before him : one he finds to be the well
known mineral, corundum, and consequently A1203 (alumina) ; and the second he finds to be
ordinary quartz, and consequently SiO2 (silica), according to the commonly received formula.
He has also before him a third mineral, one that gives the reactions of alumina and silica, and
yields these separate bodies on analysis. Naturally, therefore, he writes the formula (assuming
the two componen'ts to be in equal atomic proportions) A1203, SiO3. But, to his bewilderment,
he finds it given in modern books as A12SK)5. Practically, we do not want te know how
much aluminium, silicon and oxygen, are present in a body of this kind, but how much alumina
and silica ; and the first formula shews us this, or enables us to determine it at once. Were
only simple elements and their complex combinations known to us, the new views, carried out
properly to their full conception, might pass without opposition ; but the question becomes
entirely altered by the occurrence of simple binary compounds so abundantly in the free state.
In mineral analysis, and in the practical studjr of minerals, it is not possible to ignore these
binary formulae without great inconsistency. Among other works, they are retained essentially,
we are glad to find, in the standard and very copious " Handworterbuch der Chemie," now being
published under the editorship of Dr. Von Fehling of Stuttgart. See also Von Kobell'a remarks
on this subject in the 5th edition of his "Mineralogie :" 1878.
28 BLOWPIPE PRACTICE.
ing the latter, is to boil or warm the powdered substance in a test-tube
with a few drops of nitric acid, and after half-filling the tube with
distilled water, to drop into it a small fragment of molybdate of
ammonia. In the presence of phosphoric acid, this will turn yellow
immediately, especially if the solution be warmed, and a canary -
yellow precipitate (soluble in ammonia) will rapidly form. All
natural phosphates, with the exception of the rare phosphate of y ttria,
xenotime, are dissolved or readily attacked by nitric acid; and
xenotime, if in fine powder, is generally attacked sufficiently to yield
the reaction. Phosphates may also be decomposed by fusion, in fine
powder, with three or four parts of carbonate of soda in a platinum
spoon or loop of platinum wire. An alkaline phosphate, soluble in
water, is formed by this treatment — with xenotime as with other
phosphates — and the solution, rendered acid, may then be tested by
molybdate of ammonia. Or it may be rendered neutral by a drop of
acetic or very dilute nitric acid, and tested with a fragment of nitrate
of silver, in which case a canary-yellow precipitate will also be pro-
duced. Or it may be tested by adding to it a small fragment or two
of acetate of lead, and fusing the resulting precipitate on charcoal.
On cooling, the surface of the fused bead shoots into crystalline facets.
(11) Boron. — Present in nature in an oxidized condition only, as
boracic acid. This occurs : (1), in the hydrated state; (2), in combi-
nation with bases, in the group of borates ; and (3), in certain so-
called boro-silicates. Boracic acid (or anhydride) and many borates
and boro-silicates impart per se a green coloration to the flame-border,
and all produce this coloration if previously saturated with sulphuric
acid. In some few silicates, however, in which little more than traces
of BO3 are present, the reaction is scarcely or only very feebly
developed unless the test-substance, in fine powder, after treatment
with sulphuric acid, and partial desiccation, be moistened with
glycerine, according to a process first made known by lies. But a
similar flame-coloration is produced by phosphates and certain other
bodies. For the proper detection of borates, therefore, the following
long-known method should be resorted to. The test-matter, in fine
powder, is saturated with sulphuric acid, and allowed to stand for a
minute or two; a small quantity of alcohol is then added, and the
mixture is stirred and inflamed. The presence of BO3— unless in
REACTIONS. 29
very minute or accidental quantity — •communicates to the point and
edges of the flame a peculiar green or yellowish-green colour. Phos-
phates do not colour the flame under this treatment.
(12) Carbon. — Occurs in the simple state in the diamond and
graphite, and practically so in the purer kinds of anthracite ; also
combined with hydrogen, &c., in ordinary coals and bituminous sub-
stances ; and in an oxidized condition, as carbonic acid (or anhydride)
in the group of carbonates. Free (mineral) carbon is infusible and
very slowly combustible in the blowpipe-flame, a long continued
ignition being necessary to effect the complete combustion of even
minute splinters. Ignited with nitre, it deflagrates and is dissolved,
carbonate of potash resulting. "With other blowpipe reagents it
exhibits no characteristic reactions. The presence of carbonic acid
in carbonates is readily detected by the effervescence which ensues
during the fusion of a small particle of the test-substance with a
previously-fused bead of borax or phosphor-salt on platinum wire,
CO2 being expelled. All carbonates, even in comparatively large
fragments, dissolve readily under continued effervescence in these
fluxes. A mixture of carbonate of lime in silicates, sulphates, and
other bodies, may thus be easily recognized. (See Appendix, No. 19),
It should be remembered, however, that bodies which evolve oxygen
on ignition, produce also a strong effervescence by fusion with borax •
but, with the exception of binoxide of manganese, very few of these
bodies are of natural occurrence.
(13) Silicon. — This element occurs in nature only io an oxidized
condition, as Silica, SiO2. The latter compound, in the form of
quartz and its varieties, is the most widely distributed of all min-
erals. In the various opals, it occurs combined with water, and in
combination with bases (especially with A1203, Fe203, CaO, MgO,
FeO, Na2O, and K20), it forms the large group of silicates. In the
simple state, silica is quite infusible in the ordinary blowpipe-flame.
With carb. soda, it dissolves with effervescence (due to the expulsion
of CO2 from the flux), and it forms with that reagent, in proper pro-
portions, a permanently clear glass — i.e., a glass that remains clear
on cooling. To obtain this, the flux should be added little by little,
until perfect fusion ensue: with too much soda, the bead is opaque.
30 BLOWPIPE PRACTICE.
Borax attacks silica very slowly, and in phosphor-salt it is still more
slowly attacked. A portion may be taken up by the hot glass, but
this is precipitated on cooling, and the glass becomes opalescent.
(See Appendix, No. 15). Silicates vary greatly in their comport-
ment before the blowpipe, the variation depending chiefly on the
relative proportions of silica and base, and on the nature of the base.
Many silicates are infusible ; others become vitrified on the thin
edges; and others, again, melt more or less readily, — most of the
so-called zeolites (hydrated silicates of alumina, lime, soda, &c., espe-
cially characteristic of trap rocks) exhibiting the phenomenon of
intumescence. Silicates, as a rule, are very readily detected by their
comportment with phosphor-salt : the bases are gradually taken up,
whilst the silica remains for the greater part undissolved, forming a
" silica-skeleton/' This is seen as a diaphanous, flocculent mass (of
the shape and size of the test-fragment) in the centre of the hot bead.
A small portion of the silica, or in one or two exceptional cases the
greater part of it, may be dissolved with the bases, but this precipi-
tates as the glass cools, and renders it vsemi- translucent or opalescent.
Practically, silicates are readily distinguished from phosphates, car-
bonates, sulphates, <fec., by these reactions with phosphor-salt : namely,
very slow or partial solution, and formation in most cases of a silica
skeleton or opalescent glass. The trial is best made on platinum
wire, and the test-substance should be added, if possible, in the form
of a thin scale or splinter. (See Appendix, No. 15).
II. — UNOXIDIZABLE METALS.
As regards their blowpipe reactions, the metals of this group fall
into two series : Infusible metals, comprising platinum (with palladium,
<fec. ) ; and Fusible metals, comprising gold and silver. Strictly, silver
absorbs a small amount of oxygen when fused in contact with the
atmosphere, but the oxygen is evolved as the metal solidifies. It is
this which causes cupelled silver to " spit " or throw out excrescences,
if the button be allowed to cool too quickly. All the metals of this
group (palladium slightly excepted) retain a bright surface when
exposed to the action of an oxidating flame.
(14) Platinum. — Occurs in the metallic state, alloyed with indium,
«,nd commonly with small quantities of other metals. Practically,
REACTIONS. 81
infusible ; but the point of a wire of extreme tenuity may be rounded
in a well-sustained flame. Not attacked by the blowpipe fluxes.
(15) Gold. — Occurs principally in the metallic state, alloyed with
variable proportions of silver. Also, but far less commonly, com-
bined with mercury in some varieties of native amalgam, and with
tellurium in some rare tellurides. In the metallic condition, or per*
haps as an arsenide or sulphide, it is present likewise as an accidental
component in many examples of arsenical pyrites, iron pyrites, copper
pyrites, zinc blende, &c., in the proportions of a pennyweight or two,
to several ounces, per ton. Fuses readily on charcoal before the
blowpipe, and retains its bright surface in an oxidating flame* Not
attacked by the blowpipe fluxes. Separated from silver by fusion
with bisulphate of potash in a platinum spoon, the silver becoming
dissolved, or (if the silver be not in too small a quantity) by dilute
nitric acid moderately warmed. In the latter treatment, the gold
separates as a dark mass or powder. This assumes a yellow colour and
metallic lustre by compression with a glass rod or other hard body.
An alloy of gold containing but little silver is merely blackened by
the acid. In this case it may be folded in a small piece of pure sheet
lead with a piece of silver of about twice or three times its size, and
cupelled before the blowpipe (Operation 9, page 19). The alloy is
then readily attacked by the acid, and the silver is dissolved out*
(16) Silver.— This metal occurs in nature under various conditions :
principally in the simple state, as an amalgam with mercury, and as
a sulphide, sulphantimonite, sulpharsenite, and chloride; less com*
monly as a selenide, telluride, antimonide, sulpho-bismuthite, bromide
and iodide. It occurs also as an " accidental component " in many
varieties of iron pyrites, <fec.> and in almost every example of galena.*
Metallic silver melts readily before the blowpipe, and the fused globule
retains a bright surface after exposure to an oxidating flame. In a
prolonged blast a slight brownish-red sublimate is deposited on the
charcoal, the sublimate being more distinctly red in the presence of
lead or antimony, but in the latter case it is scarcely observable until
these metals become for the greater part volatilized. Silver oxide
becomes rapidly reduced on charcoal. It is dissolved by borax and
phosphor salt, forming glasses which are indistinctly yellowish whilst
\ ~ J ~ **
* For its detection in this mineral, see the foot note on page 19.
BLOWPIPE PRACTICE.
hot, and opaline or opaque-white on cooling. Metallic silver is
attacked with similar results by these fluxes, and also by bisulphate
of potash. In all ordinary cases the presence of silver in minerals is
best detected by reduction and cupellation with lead, as described
under Operations 8 and 9, pages 16-20, above. Or a kind of scorifi-
cation process may be employed, by mixing the unroasted ore (to
avoid loss of silver) with a little borax, and fusing it in a small
cylindrical case of pure lead-foil, made by folding a piece of foil
round the end of a common pencil, and flattening down the projecting
edges. The mixture is inserted into this little case by a folded slip
of glazed paper,- or a small scoop of horn or thin brass. The upper
edges of the foil being then pressed or flattened down, the case with
its contents is sunk in a sufficiently deep charcoal-cavity, and exposed
for a few minutes, first to a reducing, then to an oxidating, and then
again to a reducing flame, until the rotating globule shew a clean,
bright surface. If the metallic button, after separation on the anvil
from accompanying slag, be too large to be cupelled in one operation,
it may be flattened out and cut into several pieces. These can be
concentrated on separate cupels, and then cupelled together as
described at page 19.
III.— VOLATILIZABLE METALS.
*
The metals of this group are characterized (tin excepted) by the
emission of more or less copious fumes when ignited before the blow-
pipe. Tin becomes rapidly coated with a crust of oxide, and is only
slightly volatile. In arsenic and osmium the evolved fumes are accom-
panied by a marked odour. Tellurium, antimony, arsenic, bismuth,
lead, thallium, cadmium and zinc, form characteristic sublimates on
charcoal, and (cadmium and bismuth excepted) these metals impart
a marked coloration to the flame-border. Tin forms only a slight
sublimate. Lead, thallium and tin give malleable globules; tellurium,
antimony and bismuth, brittle globules. The other metals of the
group volatilize without fusion, or without yielding metallic globules
011 charcoal.
(17) Tellurium. — This metal is of rare occurrence. It is found
occasionally in the simple state, and also combined with gold, silver,
lead, and other bases in the small group of tellurides. The metal
fuses easily, volatilizes, tinges the flame green, and forms a white
REACTIONS.
deposit of TeO2 on charcoal. In the open tube, TeO2 is
as a white coating, but this, when the flame is directed
into small colourless drops, a character by which it is
from the sublimate formed by antimony and antimonial compounds,-
Tellurides produce the same general reactions. The presence of
tellurium may also be recognized by fusing the test-matter with carb.
soda on charcoal, cutting out the fused mass, and dissolving the
resulting alkaline telluride in hot water. The solution has a dis-
tinct reddish-purple colour. A purple (or reddish) coloration is also
obtained by warming the test-substance, in powder, with concentrated
sulphuric acid.
(18) Antimony. — Occurs in nature (though rarely) in the simple
state, and in one or two rare antimonides. Also much more abundantly
in combination with sulphur ; and as a sulphur- acid in combination
with lead, copper^ and other bases, in the somewhat extensive group
of sulphantimoiiites. It also occurs in an oxidized condition, but in
that state is comparatively rare. The presence of antimony is-
revealed in these minerals by the emission of copious white fumesr
with deposition of a white coating on charcoal, and green coloration
of the flame. The white coating if moistened with nitrate of cobaltr
and gently ignited, assumes on cooling a greenish colour. By treat-
ment in the open tube, a dense white, or greyish-white, uncrystalline
sublimate is produced. This is soluble in tartaric acid. If a bead
of sulphide of sodium (obtained by the fusion of some carb. soda with
a little borax and some bisulphate of potash in a reducing flame on
charcoal) be placed in the solution, an orange-red precipitate (Sb'2S3)
is produced. (See Appendix, No. 13.) Sulphantimonites are par-
tially dissolved by a solution of caustic potash. Hydrochloric acid
throws down from the solution the same orange-coloured precipitate
of Sb2S3. Antimonial oxides dissolve readily in borax and phosphor-
salt, forming beads which are slightly yellowish or colourless after
exposure to an oxidating flame, and grey, from reduced particles of
metal, when exposed to the R. F. Prolonged blowing, however,
causes the metal to volatilize, and the glass becomes clear. The
phosphor-salt bead treated with tin, becomes on cooling dark grey or
black, and quite opaque. This reaction is characteristic of antimony
and bismuth compounds.
4
34 BLOWPIPE PRACTICE.
(19) Arsenic. — Occurs, more especially, under the following con-
ditions : In the simple metallic state (usually impure from the
presence of small quantities of Sb, Fe, Co, &c.). In various arsenides,
combined chiefly with cobalt, nickel, and iron. In combination with
sulphur, alone, and combined with bases (Ag, Cu, &c.), forming a
small series of sulpharsenites. In combination with oxygen, as
arsenic acid, alone, and combined with CuO, NiO, and other bases
forming the various arseniates. In these conditions its presence, as a
rule, is easily recognized by the strong odour of garlic evolved during
the ignition of the mineral on charcoal. In substances of a non-
metallic aspect, the odour is more strongly developed, if the test-
matter be mixed with carb. soda. Metallic arsenic sublimes, without
melting, in copious fumes, which form a white or grayish deposit on
the charcoal. A clear blue tint is communicated at the same time to
the flame-border. Similar fumes are also emitted (though less copi-
ously) by most arsenides and sulpharsenites, as wtll as by oxidized
compounds, as the arsenic acid of the latter is readily reduced on
charcoal. Non-oxidized arsenical bodies when ignited in the open
tube (Operation 5, page 11), evolve arsenic, which becomes oxidized
into arsenious acid As2O3, by the current of air passing up the tube ;
and this compound is in great part deposited in the form of minute
crystals (octahedrons), a short distance above the test-matter. If the
tube be of very narrow diameter, however, or if it be held too hori-
zontally, a gray or black deposit of metallic arsenic, or a yellow or
red deposit of sulphide of arsenic, may also be formed. The crystals,
although very minute, can generally, from their glittering facets, be
recognized by the unaided eye, but a strong magnifying glass or small
microscope is required for their proper observation. All arsenical
bodies, either per se, or when mixed with dry carb. soda, neutral
oxalate of potash, or other reducing agents, and ignited in a narrow
tube closed at one end, form a dark shining "mirror" on the inside
of the neck of the tube. The reaction is assisted in the case of oxi-
dized bodies which contain merely a small amount of arsenic, by
placing a charred match or slip of charcoal in the tube, above the
assay-mixture, and igniting first the charcoal and then the mixture,
so as to drive the fumes over the charcoal. A dark metallic ring is
formed by this method, even if the test-substance contain only traces
of arsenic ; and if the charcoal be shaken out of the tube, held against
REACTIONS. 35
the side. of the flame until ignited, and then brought quickly under
the nose, the presence of the slightest trace becomes revealed by the
characteristic garlic-like odour which is then emitted.
Non-oxidized arsenical minerals possess a metallic aspect, or, in
default of this, are readily inflammable. Arseniates, on the other
hand, never present a metallic lustre, and none are inflammable.
Many cupreous arseniates deflagrate strongly when ignited 011
charcoal. Arsenic acid, As205 (both alone, and in some arseniates),
gives off oxygen on strong ignition, and becomes volatilized in the
condition of As203.
(20) Osmium. — -This metal is of quite exceptional occurrence. It
is found in only one mineral, Osinium-Iridium, and is thus often
classed as a so-called "platinum metal;" but its general characters
and reactions give it a place near arsenic. Osmium -Iridium remains
unchanged before the blowpipe, unless the osmium greatly prepon-
derate (as in the variety known as sisserskite), in which case part of
the osmium is volatilized. All varieties when fused with nitre in
the closed tube or on charcoal, emit the penetrating disagreeable
odour of osmic acid. Osmium, itself, volatilizes without fusing,
emitting necessarily the same odour ; and in a finely divided state it
is inflammable. If volatilized in the pale flame of alcohol, or that of
the Bunsen burner, it renders the flame highly luminous.
(21) Mercury. — Occurs sparingly in the simple state; in silver
and gold amalgams ; and in certain seleiiides. More abundantly as
a sulphide — Cinnabar, the only ore of mercury.* Sparingly, also, in
some varieties of grey copper ore (tetrahedrite) ; and in combination
with chlorine, in native calomel. In these compounds, its presence
may be readily ascertained by mixing the test-matter with some
perfectly dry carb. soda, iron filings, neutral oxalate of potash, or
other reducing substance, and igniting the mixture in a closed tube
of narrow diameter. The metal volatilizes, and deposits itself on the
neck of the tube in the form of a dark grey sublimate. If this be
rubbed by an iron wire, it runs into fluid globules which can be
* Red ochre is frequently mistaken by explorers for cinnabar. Apart from the high sp. gr.
of the latter, the two may be easily distinguished by an ignited lucifer match. Held (in the
form of a small fragment) in the match flame, cinnabar takes fire and volatilizes ; red ochre
blackens and becomes magnetic.
36 BLOWPIPE PRACTICE.
poured out of the tube, and which are easily recognized as metallic
mercury. Without the reducing agent, many of these mercurial
compounds (cinnabar, calomel, &c.) sublime without or with only
partial decomposition. When mercury is present in traces only, a
piece of gold-leaf, twisted rqund an iron wire or glass rod, may be
inserted into the mouth of the flask. The gold is whitened by a
mere trace of the volatilized metal.
(22) Bismuth. — Occurs in nature chiefly in the simple metallic
state. Found also, but more sparingly, in combination with tellu-
rium, selenium, and sulphur, and with bases in sulpho-bismuthites.
Occasionally, likewise, in an oxidized condition (Bi203) as bismuth
ochre (commonly mixed with some carbonate of bismuth), and in a
single rare silicate, arseniate, and vanadiate. Metallic bismuth fuses
readily, and gradually volatilizes, depositing a dark yellow ring of
oxide on the charcoal. The latter volatilizes in the inner flame
without colouring the flame-border. Bismuth oxide is at once
reduced and volatilized on charcoal. It dissolves in carb. soda in
an oxidating flame, very readily, if a platinum wire or other non-
reducing support be used. The glass is yellow or yellowish-brown
whilst hot, pale yellow and opaque when cold. In borax and phos-
phor-salt, it dissolves also readily. The borax glass in the O. F. is
yellowish, hot, and very pale yellow or white aud opaline when
cold. In the R. F. the glass becomes clear from separation of the
reduced metal. The phosphor-salt glass in the O. F. may be rendered
milk-white by flaming or saturation. In the R. F., with tin, it is
transparent whilst hot, and very dark-grey or black on cooling. In
this respect, the reaction resembles that produced by antimony. The
presence of bismuth, in bodies generally, is detected by the dark -yellow
coating or ring-deposit formed on charcoal by the fusion or ignition of
the test-substance with carb. soda. This deposit is distinguished from
that formed by lead, by its deeper colour, and by imparting no colour
to the flame. Also, by the black bead formed by it (or by another
portion of the test-substance) with phosphor-salt and tin in a reducing
flame, as described above. The button of reduced bismuth, moreover,
is brittle ; that of lead, malleable. These metals may also be dis-
tinguished by the sublimates which they form when ignited on
charcoal with iodide of potassium, according to the method of Merz ;
REACTIONS. 37
or by fusion, first with sulphur, and then with iodide of potassium,
according to the more delicate process of Yon Kobell. With lead,
the sublimate is lemon-yellow, or in thin layers, greenish-yellow ;
whilst with bismuth it presents a vivid scarlet colour, or a ring of
this around the outer edge of a yellowish deposit. When a very
small amount of bismuth oxide is associated with excess of lead oxide,
Cornwall recommends a modification of the process, as follows : the
substance, mixed with about an equal quantity of a mixture of five
parts sulphur and one part iodide of potassium, is ignited in a test-
tube by the spirit-flame or bunsen burner. The presence of bismuth
is indicated by a scarlet or orange-coloured band, which forms above
the yellow sublimate occasioned by the lead. (See, also, page 67, the
characteristic reaction with hydriodic acid, lately discovered by Dr.
Haanel.)
(23) Lead. — The occurrence of native lead is quite exceptional.
The metal occurs most commonly as a sulphide (galena), and not
uncommonly as a sulphantimonite (and to some extent as a sulph-
arsenite). Also, frequently in an oxidized condition, as a sulphate,
carbonate, phosphate and arseniate. Among rarer (natural) com-
pounds, it occurs as a selenide, telluride, chloride, oxide, chromate,
vanadiate, tungstate, molybdate, antimoniate. The presence of lead
in bodies generally is made known in blowpipe testing by the two
following characters : the formation of a yellow ring-deposit on
charcoal, and the ready formation of a malleable metallic globule —
these reactions requiring, however, in some few cases, the assistance
of carb. soda or other reducing flux for their proper manifestation.*
Lead oxide is immediately reduced on charcoal, colouring the flame
light-blue. It dissolves readily in the blowpipe fluxes if the fusion
be performed on a non-reducing support. The glasses, produced by
an oxidating flame, are colourless or yellowish, and become opaque
by saturation or flaming. (See Appendix, No. 6.)
(24) Thallium. — This new metal is only known to occur (in very
minute quantities) in certain examples of iron pyrites, copper pyrites,
zinc blende, native sulphur, and some few other minerals. Its chief
characteristic is its property of imparting a brilliant green coloration
* In the presence of sulphur, more especially, the reduction is facilitated by the addition of
a small piece of iron wire. See note at foot of page 19.
38 BLOWPIPE PRACTICE.
to the Bimsen or blowpipe flame. In other respects its reactions
much resemble those of lead, but the oxidized ring-deposit (best seen
on a porcelain support or on the surface of a boneash cupel) is dark
brown. (See Appendix, No. 14).
(25) Cadmium. — As an essential component, this metal occurs
only in a rare sulphide, greenockite. It is present, however, in small
quantity in many examples of zinc blende, and in certain varieties
of the carbonate and silicate of zinc. Metallic cadmium, on charcoal
before the blowpipe, shrinks somewhat together, blackens, takes fire
slightly, and becomes volatilized in dense brown fumes. These
deposit themselves in the form of a brownish-black and reddish-
brown coating (CdO), with a tinge of brownish-yellow towards the
outer edge. The deposit is at once reduced and dissipated by either
flame, without communicating any colour to the flame border. In
both the closed and open tube, if the latter be of narrow diameter, a
metallic sublimate is formed near the assay -matter, and a dark-brown
sublimate, with yellowish edge, higher up the tube. Fused with
phosphor-salt on charcoal, metallic cadmium (like metallic zinc) gives
rise as the bead cools to slight detonations and flashes of light.
Cadmium oxide 011 a non-reducing support is infusible, and remains
unvolatilized. With borax and phosphor-salt it forms colourless
beads which become milk-white and opaque by saturation or flaming.
On charcoal the oxide is rapidly reduced and volatilized, but yields
no metallic globule. The dark red -brown sublimate, formed on char-
coal or better on a porcelain support by the fusion of a cadmiferous
substance with carb. soda, is the principal blowpipe-reaction of the
metal. In the presence of much zinc, the blast must not be con-
tinued too long, otherwise the dark deposit of cadmium oxide,
formed before the deposition of the zinc oxide, may be obscured
by the lattar. For the detection of cadmium in the presence of zinc
generally, see Appendix, No. 17.
(26) Zinc. — Of doubtful occurrence in the native state. Found
principally as a sulphide, oxy-sulphide, oxide, sulphate, carbonate,
silicate and aluminate. Metallic zinc, when ignited on charcoal,
burns vividly with transient flashes of green, blue and greenish-white
flame, and throws off dense fumes which become oxidized and
deposited as a coating on the charcoal. This coating (ZnO) is palo"
REACTIONS. 39
yellow and phosphorescent when hot, and white when cold. It is
not driven off by the reducing flame, unless the blast be long con-
tinued. If moistened with a drop or two of nitrate of cobalt, and
ignited by an oxidating flame, it becomes of a light-green colour on
cooling. Zinc oxide forms with borax and phosphor-salt colourless
beads, which become milk-white and opaque by saturation or when
flamed. Metallic zinc fused with a bead of phosphor-salt on char-
coal, detonates slightly and emits flashes of light after removal from
the flame — a reaction first noticed by Wohler, and considered to arise
from the formation of a zinc phosphide.* It is manifested, however,
not only by zinc, but also by cadmium, aluminium and magnesium,
and to some extent by iron pyrites, arsenical pyrites and several
other minerals ; but it is not produced by tin, lead or thallium. . The
presence of zinc, in bodies, is best detected by fusing the substance,
in powder, with two or three parts of carb. soda, and a little borax
on a clean piece of charcoal. A characteristic ring-deposit (lemon-
yellow and phosphorescent, hot ; white, cold ; and green, on cooling,
after ignition with cobalt solution) is readily obtained as a rule by
this treatment. In the case of silicates (and indeed in all cases) the
deposition of this ring-coating is facilitated by first fusing the test-
substance with phosphor-salt, and then crushing the saturated bead
on the anvil, and re-melting it with carb. soda on charcoal.
(27) Tin. — Native tin is of doubtful occurrence. The metal of
commerce is obtained entirely from the binoxide, known in its
natural occurrence as cassiterite or tinstone. Tin occurs also, but
rarely, as a sulphide in tin pyrites ; and the binoxide is present in
small quantities in tantalates generally, and in certain titaniates, sili-
cates and other compounds. Metallic tin melts easily, without colour-
ing the flame. Before the outer flame it rapidly oxidizes and gives off
slight fumes, which form a coating on the fused globule and on the
charcoal immediately around the latter. The coating is slightly-
yellowish whilst hot, and white or greyish-white when cold, and it is
not driven off by the flame, but ill a long continued blast it may
become reduced. When moistened with a drop of cobalt solution
* I have tried, but without success, to make this reaction available for the detection of
phosphates by fusing these, in powder, with boracic acid, borax and other reagents, and then
adding a piece of metallic zinc to the glass. The reaction, although sometimes produced by
this treatment, is too uncertain to serve as a test,
40 BLOWPIPE PRACTICE.
and ignited, it becomes on cooling blueish-green. SnO and
(neither of any interest, mineralogically) burn on ignition, and
become converted into binoxide. The latter SnO, is infusible by
the blowpipe, but on charcoal, in a well-sustained blast, it is reduced
to metal. The reduction is greatly facilitated by the addition of carb.
soda, neutral oxalate of potash, or a mixture of carb. soda and cyanide
of potassium, the latter acting most rapidly. In borax, the binoxide
is very slowly attacked and dissolved; and phosphor-salt acts upon it
still more slowly. With both reagents the glass remains clear when
flamed. With soda in the outer flame, it forms, with effervescence, a
greyish- white infusible mass. In a good reducing flame (especially if
a little borax be added to promote fusibility) it yields reduced metal.
As pointed out by Berzelius, a small portion of borax should always
be added to the soda in the examination of tantalates and infusible
bodies, generally, for the presence of tin. A malleable, easily oxidizable,
metallic globule is then, as a rule, obtained without difficulty; but when
a trace only, or very small percentage of tin is present, the regular
reducing process (explained on page 17) must be resorted to. A
button of metallic tin may be distinguished by its malleability, feeble
sublimate and ready oxidation, from other metallic globules as
obtained by the blowpipe. In nitric acid it becomes converted into
a white insoluble powder (SnO2), behaving in this respect like anti-
mony ; but the latter metal gives a brittle button, and also a copious
sublimate or ring-deposit which volatilizes wholly or in chief part,
and communicates to the flame a greenish coloration. From silver,
the tin globule is distinguished by its ready oxidation, and its con-
version into insoluble binoxide by nitric acid — silver, in that reagent,
dissolving rapidly. From lead and bismuth, it is distinguished also
by this acid reaction, and by the non-formation on charcoal of a
yellow sublimate. When small pieces of tin and lead (or tin and
thallium, or tin and bismuth), are melted together, a remarkable
oxidation ensues — the fused mass becoming rapidly encrusted, and
continuing, after withdrawal from the flame, to push out excrescences
of white and yellow oxides. (See Appendix, No. 21).
IV. FLUX-COLOURING METALS.
The oxides of the metals of this group possess, in common, the
property of communicating distinct and more or less characteristic
REACTIONS.
41
colours to borax and phosphor-salt glasses before the blowpipe. By
some, also, a colour is imparted to the soda bead ; but most of these
oxides are insoluble in carb. soda. They fall into two leading sections,
as in the following arrangement :
B. — Not reducible from an oxidized
or other condition by the blowpipe.
Bl. — The borax-glass not rendered
opaque by naming :
Manganese. Chromium. Vana-
dium.
B2. — The borax-glass converted by
flaming into a dark or light enamel :
Uranium. Cerium. Titanium.
A. — "Reducible from an oxidized or
other condition by the blowpipe.
A1. — Fusible, and therefore obtained
by reduction in metallic globules :
Copper.
A2. — Infusible (practically), and
therefore obtained by reduction in the
form of separate grains or scales :
t Magnetic :
Nickel. Cobalt. Iron.
ft Non-magnetic :
Tungstenuin. Molybdenum.
(28) Copper. — This metal occurs frequently in the native state.
Also as a base in numerous sulphides, and in certain arsenides,
selenides, sulpharsenites and sulphantimonites. In combination like-
wise with chlorine. Also in an oxidized condition as Cu20 and CuO ;
and in the latter form, as a base, very commonly in arseniates, phos-
phates and carbonates; and less commonly as a sulphate, chromate,
vanadiate and silicate. Metallic copper, on charcoal, melts before the
blowpipe into a malleable globule, the surface of which, if exposed to
the outer flame, becomes quickly tarnished by a black coating of
oxide. This oxide imparts to the flame-border a rich green colour.
Cupreous sulphides, arsenides and related compounds bepome con-
verted by careful roasting, with avoidance of fusion (see the Opera-
tion, page 11), into the same black oxide; and a roasting of this
kind is always necessary as a preliminary to the reduction of the cop-
per, and its detection by fusion with borax. Both the red and black
oxides fuse readily and become reduced on charcoal. With borax
and phosphor-salt, the glass after exposure to an oxidating flame,
is green whilst hot, and clear-blue when quite cold — unless much
iron or nickel be present, in which case it retains its green colour
on cooling. In a reducing flame, especially on charcoal, the glass
becomes almost colourless, and on cooling turns brick-red and
opaque. This reaction (which serves for the detection of copper in
the presence of most other flux-colouring bodies) is developed more
42 BLOWPIPE PRACTICE.
easily with borax than with phosphor-salt, but when very little
copper oxide is present in the glass, it is not always obtained without
long blowing. If, however, a small piece of tin or iron-wire be stuck
through the soft glass, and the bead be then again submitted for a
few moments to a reducing flame, the opaque red glass (due to the
reduction of the CuO to Cu20) is readily produced. In place of iron-
wire, a small fragment of any substance containing FeO (as iron-
vitriol, magnetic iron ore, spathic iron, &c.) may be used to promote
the reduction, the FeO becoming converted into Fe203 at the expense
of some of the oxygen of the copper compound. The fusion may
then be performed on platinum wire ; but, in any case, the bead
m.ust not be kept too long in the flame, as the whole of the copper-
oxide might be reduced to metal, and the glass become colourless by
prolonged fusion. By this reaction, the presence of copper in bodies
generally (after the preliminary roasting of those which contain
sulphur, antimony, &c.) is unmistakably revealed. Another charac-
teristic reaction is the bright azure-flame produced by chloride of
copper. The slightly-roasted substance may be moistened with a
drop of hydrochloric acid — or fused with chloride of silver — and
held just within the point of an oxidating flame. If copper be pre-
sent, the flame around the test-substance will exhibit a brilliant
azure coloration. The test may also be made by simply fusing the
substance on platinum wire with phosphor-salt, and then adding
some chloride of sodium to the bead. (See, also, Appendix, No. 12).
(29) Nickel. — Occurs in small and variable proportions in most
examples of meteoric iron, and also in some meteoric stones as a
phosphide and sulphide. In minerals proper, it is found more
especially as an arsenide, antimonide, sulphide and sulpharsenite.
It occurs also in an oxidized condition, at times as a simple oxide
in coatings on nickel ores, but more commonly as an arseniate, car-
bonate, sulphate and silicate. In some (mostly magnesian) silicates,
and in the apple-green variety of calcedony, known as chrysoprase,
it is present in minute quantity as the colouring material of the
substance. Metallic nickel is infusible in the blowpipe flame. As
obtained by reduction of the oxide NiO by carb. soda or other
reducing agent on charcoal, it forms numerous minute particles of a
shining white colour. These are strongly magnetic. Sulphides,
ABACTIONS. 43
arsenides and related compounds, become converted by roasting into
this oxide. The latter is unaltered per se by the blowpipe flame.
With borax, it forms in the O.F. a glass which is amethystine in
colour whilst hot (if the NiO be in moderate quantity), and pure
brown or yellowish-brown when cold. If not too deeply coloured,
the glass on the addition of a carbonate or other salt of potash in
excess, is rendered more or less distinctly blue or greyish-blue. The
reaction, however, is not very strongly marked, and except under
special conditions it can scarcely be regarded as characteristic. In
the R.F., the borax glass becomes grey and opaque on cooling, from
precipitation of reduced particles of metal. This is the characteristic
blowpipe-reaction of nickel. It serves for the detection of that
metal (when occurring in more than a very small percentage) in the
presence of cobalt and iron oxides, but it is masked by the presence
of copper. When copper and nickel occur together, however, the
presence of the latter may be suspected by the borax glass, after
exposure to an oxidating flame, remaining green when cold ; whereas
with copper oxide alone, it becomes clear blue on cooling. The
reaction, nevertheless, is merely suggestive, as it is produced by other
metals, Fe, Or, &c., when associated with copper. With phosphor-
salt, NiO produces much the same reactions as with borax, only the
glass in the oxidating flame is less distinctly coloured. With carb.
soda on charcoal, as stated above, it is reduced to minute shining
particles of magnetic metal.
(30) Cobalt. — This metal, as an essential constituent, occurs only
in a small number of minerals, and chiefly as an arsenide and sul-
phide, separately and combined. More rarely it is found as a selenide
and oxide, and occasionally as an arseniate ; but it is present in
traces, as an accidental component, in many sulphides and arsenides,
as in varieties of arsenical pyrites, cubical pyrites, &c. The metal
itself is practically infusible. Sulphides, arsenides, &c., become con-
verted by roasting into the oxide CoO. This, with carb. soda on
charcoal, is readily reduced to shining, magnetic particles of metal.
With both borax and phosphor-salt, and in both flames, the oxide
forms glasses of a deep blue colour, even when present in traces only.
This is the characteristic reaction. When much iron, nickel, or
copper is present, the glass however is dark green ; but copper and
44 BLOWPIPE PRACTICE.
nickel may be removed by reduction in the inner flame (especially if
a small piece of tin be added to the glass on charcoal), and the tint
derived from iron is generally overpowered in the outer flame by the
much stronger reaction of the cobalt.
(31) Iron. — Occurs in the simple state in meteoric iron, though
commonly alloyed with a small percentage of nickel. Occurs also,
and in numerous localities, in various sulphides, arsenides and sul-
phur-salts ; and in an oxidized condition as FeO + Fe2O3 in magnetic
iron ore, as Fe203 in haematite, &c. ; and as FeO or Fe2O3 in numerous
silicates and other oxygen salts. Metallic iron is practically infusible
in the blowpipe-flame, but the extremity of a very thin wire may be
oxidized and then fused. Hard wires fuse in general the most easily,
and the fusion is accompanied by a rapid scintillation or emission of
sparks, whilst very frequently a thin green flame streams from the
point of the wire. The latter reaction is due to the presence of
phosphorus. (See Appendix, No. 11.) Sulphides, arsenides, &c.,
become converted into the sesquioxide Fe203 (often termed "red
oxide") by roasting. This oxide, by fusion with carb. soda and a
little borax on charcoal, is easily reduced to shining particles of
metal, strongly attractable by the magnet. On platinum wire or
other non-reducing support, it forms with soda a slaggy infusible
mass. It dissolves readily, on the other hand, in borax and phos-
phor-salt, forming glasses which are reddish or yellowish whilst hot,
and very pale-yellow or almost colourless when cold, after exposure
to the OF ; and more or less of a bottle-green colour after treatment
in the R. F., especially if a small piece of tin be added to promote
reduction, Fe2O3 becoming thus converted into FeO. All minerals
which contain 5 or more per cent, of iron become magnetic after
ignition or fusion. By this reaction, ferruginous substances may be
easily recognized, as although cobaltic and nickeliferous bodies also
become more or less magnetic on ignition, these latter bodies are of
rare occurrence. They are readily distinguished, moreover, from
ferruginous substances by the colours, &c., of the glasses which they
form with borax. When the presence of iron has been recognized in
a silicate or other body, it is often desirable to ascertain whether the
iron is present as sesquioxide Fe'^03, or partly or wholly as protoxide,
FeO. This may be determined by adding some of the test-substance,
REACTIONS. 45
in powder, to a bead of borax coloured blue by previous fusion with
a few particles of oxide of copper, and exposing the bead (in a loop
of platinum wire) to the point of the blue flame until the substance
begins to dissolve. If any FeO be in the substance, it will become
converted into Fe2O3 at the expense of some of the oxygen of the
copper oxide, and the latter will thus become reduced to suboxide^
Cu20, causing red streaks and spots to appear in the glass, as this
cools. If no FeO be present, the glass will, of course, become green
on cooling, but will remain transparent. (See Appendix, No. 5.)
A very minute trace of iron may be detected by the following
process : Fuse into a bead of phosphor-salt, on platinum wire, as
much of the substance, in powder, as the bead will take up. Then
saturate the bead with successive portions of bisulphate of potash (or
treat the. crushed bead with that reagent in a platinum spoon), and
dissolve out the soluble matters in warm water. Finally, place in
the solution a very small particle of ferrocyanide of potassium
("yellow prussiate"). If iron be present, a deep-blue precipitate
will necessarily ensue.
(32) Tungstenum or Wolframium. — This comparatively rare metal
is known in nature only in an oxidized condition, as WO3, a compound
which occurs occasionally alone, but more commonly in combination
with bases, thus forming the small group of timgstates. Tungstic
acid or anhydride WO3, is scarcely affected by the blowpipe-flame ;
but on charcoal, after long ignition in the R. F., it becomes blackened,
by conversion into W2OS. With carb. soda or neutral oxalate of
potash, it is reduced on charcoal to minute particles of metallic
timgstenum ; but if much soda be used, the portion of test-matter
absorbed by the charcoal is generally obtained (by washing in the
agate mortar, page 17) in the form of minute yellow specks, .of
metallic lustre, consisting of a compound of soda and ttmgstic oxide.
On platinum wire, with carb. soda, it dissolves more or less readily
into a yellowish glass, which becomes opaque and somewhat crystal-
line on cooling. Borax dissolves it readily. After exposure to the
O. F. the glass is yellowish and clear, but becomes- enamelled by
flaming. In the R. F., with excess of test-matter, the glass is
yellowish-brown, and by flaming or on cooling it becomes opaque.
With phosphor-salt, in a reducing flame, a deeply coloured greenish-
46 BLOWPIPE PRACTICE.
blue glass is obtained. This is the characteristic blowpipe reaction
of tungstenum compounds ; but if much iron be present, the glass
becomes deep-red. The presence of tungstenum may also be detected
by fusing the powdered test-substance with 3 or 4 parts of carb, soda
and a little nitre in a platinum spoon or loop of thick platinum-wire,
dissolving out the soluble alkaline tungstate (as explained on page 20),
decanting the clear solution, acidifying it with a few drops of hydro-
chloric acid, and placing in it a piece of zinc. A dark-blue coloration
(from reduction of the WO3 to W2O3) will rapidly result.
(33) Molybdenum. — This metal occurs in nature most commonly
in combination with sulphur, in the sulphide molybdenite, a mineral
which presents a curious resemblance to graphite in many of its pro-
perties (foliated or scaly-granular texture, softness and flexibility,
soapy feel, detonation with nitre, infusibility, &c.). It occurs also,
though rarely, in an oxidized condition as MoO3, this latter compound
being found at times alone, but more commonly combined with lead
oxide in the molybdate wulfenite. Molybdic acid or anhydride,
MoO3, melts easily on charcoal, tinges the flame yellowish-green, and
becomes gradually volatilized, forming a deposit which is slightly
yellowish whilst hot, and white when cold. When touched by the
reducing flame, this deposit assumes a dark-bluish tinge from partial
conversion into Mo203. In addition to the white coating, an indis-
tinct reddish deposit is also formed near the test-matter. With carb.
soda, reduction to minute steel-grey particles is easily effected on
charcoal. On platinum wire, solution takes place with effervescence.
With borax,before the 0. F., a yellowish glass, which becomes grey
and opaque by flaming, is formed ; and in the R. F., a brown or grey
glass, with separation of dark flecks, the latter best seen by pressing
tjie bead flat before it cools. With phosphor-salt, on cooling, and
especially after exposure to a reducing flame, a fine green glass
results. By this reaction (combined with the property of colouring
the flame pale yellowish-green,* and yielding per se or with carb. soda
a white sublimate and reduced particles of non-magnetic metal),
molybdenum compounds are chiefly recognized in blowpipe practice.
Molybdic acid and molybdates, as first made known by Von Kobell,
* Although molybdenum compounds colour the Bunsen flame very distinctly, they give no
coloured bands iu the spectroscope, but merely o continuous spectrum.
REACTIONS* 47
when warmed with sulphuric acid, produce a rich blue solution on
the addition of alcohol. If the test-substance be fused with carb. soda
and nitre, and the solution of the alkaline molybdate be treated with
hydrochloric acid and metallic zinc, a bluish colour may appear at first,
but this quickly changes to dark-brown. (See under Tungstenum,
No. 32, above.)
(34) Manganese. — -Does not occur, in nature, in the metallic state.
Occurs occasionally as an arsenide and sulphide, but is chiefly found
in an oxidized condition — mostly as MnO2 and Mn203 (these com-
pounds occurring alone, combined together, or as hydrates) ; and as
MnO in various silicates, carbonates, phosphates, tungstates, &c.
As an accidental or inessential component it is present in the latter
state in very numerous minerals. In these, the MnO generally
replaces small portions of MgO, CaO, or FeO. Manganese oxides
are not reduced by carb. soda on charcoal. Yery little of the oxide
dissolves in the flux, but this communicates to the bead a green
colour whilst hot, and a blue or greenish-blue colour when cold.
The reaction is brought out more prominently by the addition of a
little borax to the soda, as this promotes solution (see Appendix, No.
9) ; and it is also increased in intensity by melting a small portion
of nitre into the bead, or by pressing the hot bead upon a small
fragment of nitre. A greenish-blue bead of this kind is known
technically as a "turquoise enamel." Manganese oxides dissolve
readily in borax and in phosphor-salt, and the solution in the case of
the higher oxides (MnO2 especially) is accompanied by great effer-
vescence or ebullition, due to the escape of oxygen from the test-
matter. Oxygen is also evolved when these oxides are strongly
ignited per &e, as in a closed tube, &c. (See under "Oxygen," above.)
The borax glass after exposure to an oxidating flame presents a
beautiful amethystine colour. In a reducing flame it becomes colour-
less, but if allowed to cool slowly it absorbs oxygen, and the ame-
thystine or violet colour is restored. This may be prevented by
urging a stream of air from the blowpipe upon the bead, directly the
latter is removed from the flame. When very little manganese is
present in the test-matter, the formation of a violet-coloured glass is
facilitated by the use of a small fragment of nitre. The phosphor-
salt glasses resemble those produced with borax, only the amethystine
48 BLOWPIPE PRACTICE.
colour is paler, and when very little manganese is present it is scarcely
developed without the aid of nitre. The great test for the presence
of manganese in bodies, is the formation of a turquoise enamel by
fusion on platinum wire or foil with carb. soda and a little borax.
Less than one part in a thousand may be easily detected by this re-
action ; and by the addition of nitre, as described above, the reaction
becomes still more delicate. Chromium compounds when fused with
carb. soda in a reducing flame form a yellowish-green mass, which
might in some cases be thought to arise from the presence of man-
ganese. But if a greenish mass of this kind be fused with sufficient
boracic acid or silica to form a clear glass, the latter in the case of
manganese will present an amethystine colour, whilst in that of
chromium it will be emerald-green. (See Appendix, No. 16.)
(35) Chromium. — Traces of this metal occur in some varieties of
meteoric iron, but otherwise chromium is found in nature only in an
oxidized condition, as Cr203 and as CrO3. In the former state it
occurs occasionally alone, as in chrome ochre; but more commonly
in combination with iron in chromic iron ore, or, as a base, in certain
silicates, and in varieties of spinel. In many silicates it is present as
an inessential component, as in the emerald, proper. In the condition
of CrO3, it occurs in combination with lead oxide or copper oxide in
the small group of chromates. The leading blowpipe reactions of
chromic oxide are as follows : Per se, the oxide is practically un-
changed. With carb. soda, it dissolves more or less readily, forming
a yellowish, opaque bead in the outer flame, and a yellowish-green
bead in a reducing flame. If a particle or two of nitre be fused into
the bead, the latter becomes blood-red whilst hot, and light-yellow
when cold — a soluble alkaline chromate resulting. With borax and
phosphor-salt, clear, emerald-green glasses are produced, especially by
treatment in a reducing flame, and after complete cooling. Whilst
hot, the glass is yellowish or red, as in many other cases. The pro-
duction of an emerald-green glass with borax generally serves for the
detection of chromium compounds ; but the character becomes neces-
sarily masked to some extent by the presence of other flux-colouring
bodies, as iron, copper, and cobalt oxides, for example. In the
presence of bodies of this kind, chromium is best detected by fusing
the test-matter (in powder) with three or four parts of carb. soda,
REACTIONS. 49
and a little nitre in a platinum spoon or loop of stout platinum-wire.
A soluble alkaline chromate then results. The solution (see page 20),
filtered or carefully decanted from the insoluble residuum, may be
divided into two portions. One portion may be evaporated to dry-
ness, and the resulting deposit tested by fusion with borax. The
other portion may be carefully neutralized by a drop or two of dilute
nitric acid, or acetic acid, and tested with a fragment of nitrate of
silver : a red precipitate should be produced. Chromates, also, when
treated with sulphuric acid and alcohol, form a rich green solution
which remains green on dilution. Chromic acid, CrO, per se, blackens
when ignited, gives off oxygen, and becomes converted into chromic
oxide. Bichromates, and many chromates also (but not neutral
alkaline salts), produce the same reaction.
(36) Vanadium. — Occurs, in nature, only in an oxidized condition,
as V2O5, combined with lead-oxide, and more rarely with other bases,
in the small group of vanadates. On charcoal, vanadic acid, fuses
and becomes in part reduced to dark-grey or black shining scales of
suboxide. If heated on a fragment of porcelain or other non-reducing
support, it fuses without decomposition, and congeals with vivid
emission of light, on removal from the flame, into a red or dark
orange-coloured crystalline mass. With borax, it forms a clear
yellowish-green glass, and with phosphor-salt a yellow glass, on cool-
ing, after exposure to the outer flame ; and emerald-green glasses
with both fluxes, on cooling, after exposure to a reducing flame.
With hydrochloric acid and alcohol, vanadates give a green solution
which becomes light-blue on dilution (Yon Kobell). In addition to
this test, it may be observed that whilst chromium compounds give
in the O. F. with phosphor-salt (on cooling) a green glass, the glass
formed by vanadium remains yellow when cold — in the absence, at
least, of copper or other flux-colouring bodies.
(37) Uranium. — Occurs only in an oxidized condition : chiefly as
UO, IPO3 in the mineral pitchblende, and as IPO3 in uran ochre
and a few comparatively rare phosphates, sulphates, carbonates, and
silicates. The sesquioxide is infusible per se, but is blackened in the
R. F. from partial reduction to UO. It is insoluble in soda, and is
not reduced to metal by that reagent, but it is readily dissolved by
borax and phosphor-salt. The borax glass is deep-yellow in the
5
50 BLOWPIPE PRACTICE.
O. F., and dingy brownish-green, when cold, after subjection to a
reducing flame ; and, if thoroughly saturated, it may be rendered
black by naming. The phosphor-salt glasses present a striking con-
trast, in being brightly coloured : yellowish-green in the O. F., and
clear chrome-green in the B, F., especially when cold. This reaction
serves to distinguish uranium compounds from those of chromium,
&c. ; but in the presence of other flux-colouring bodies uranium is
not readily detected.
(38) Cerium. — Occurs in only a few comparatively rare minerals
— chiefly as a fluoride, or in an oxidized condition in certain silicates,
phosphates, &c. On ignition, CeO becomes converted into yellow or
reddish Ce2O3. This remains unchanged. With carb. soda, on char-
coal, it is reduced to grey CeO, but gives no metal. With borax in
the O. F. a reddish or yellowish glass is obtained, and in the B. F. a
colorless glass. Both glasses become opaque when flamed, if tolerably
saturated. With phosphor-salt, the glasses on cooling are colorless,
but they are not rendered opaque by flaming, even if strongly satu-
rated. As a rule, the presence of cerium in minerals cannot be safely
proved by the blowpipe alone.
(39) Titanium. — Occurs, in nature, in an oxidized condition only
— as TiO2 in three separate forms (Rutile, Octahedrite, Brookite),
und combined with lime, yttria, zirconia, &c., in the small group of
titaniates. In this condition it is present also in certain silicates ;
and as Ti2O3 it partly replaces Fe2O3 in titaniferous iron ores,
TiO2 becomes yellowish on ignition, but remains infusible, and re-
assumes its white colour on cooling. Moistened with nitrate of
•cobalt, and ignited, it becomes green when cold. With soda, on
•charcoal, it is not reduced to metal, but it fuses with effervescence,
•and on cooling the surface of the bead shoots into broad crystalline
facets of a pearly-grey colour. With borax, it forms in the O. F. a
yellowish glass which loses its colour on cooling, and when saturated
becomes on cooling or by flaming milk-white and opaque. In the
B. F., the glass, moderately saturated, assumes on cooling a brownish-
amethystine colour, and with more of the test-matter it becomes
blackish-blue and opaque on congealing. When flamed, a light
greyish-blue film spreads over the surface of the bead. The dark-
blue tint (Plattner calls it "brown") arises from Ti'O3; the light-blue
REACTIONS.
mirface-film from the partial oxidation of this
phosphor-salt, the glass in the O. F. is colorless or
and in the R. F., on cooling, it assumes a fine
When titanium compounds contain iron, however, the glass is deep
red-brown or blood-red. In the case of Menaccanite or Titaniferous
Iron Ore, proper, this reaction is very marked ; but it is not suf-
ficiently definite to serve for the detection of small quantities of
titanium in ordinary iron ores. In these, the presence of titanium
is most readily detected as follows : — Reduce a portion of the ore to
as fine a powder as possible ; warm this with hydrochloric acid in a
small covered beaker-glass for about half-an-hour on a sand-bath,
keeping the acid just at the boiling-point ; add a little water, and
filter from the insoluble rock-matter, <fec. ; place a piece of metallic
tin in the filtrate, and boil for ten or fifteen minutes. Thus treated,
the deep-yellow solution will quickly become greenish and then color-
less, and on the boiling being continued, a pink tinge will appear
and gradually deepen into a distinct amethystine colour. In the
absence of titanium, the solution will of course remain colorless, but
the boiling must not be discontinued too soon. The presence of
titanium in iron ores, <fec., may also be detected by fusing the test-
matter, in fine powder, with six or eight parts of bisulphate of potash
(added in successive portions) in a platinum spoon ; treating the
fused mass with a very small quantity of warm water ; decanting or
filtering from insoluble matters ; adding a few drops of nitric acid,
and then five or six volumes of water ; and, finally, boiling for ten or
twelve minutes. Titanic acid, if present, is precipitated in the form
of a white or pale-yellowish powder. This may be fused with
phosphor- salt, in a reducing flame, for the production of a characteristic
amethystine glass. As pointed out by Gustav Rose, a glass of this
kind, rendered colorless or nearly so by the O. F., and then slightly
flamed, becomes opalescent from the precipitation of numerous crys-
tals of TiO2. These are best examined, in the flattened bead, by a
microscope with object glass of moderate but not too low power.
V. — EARTH METALS.
This group is to a great extent conventional. Tantalum is placed
in the group, because in a scheme of this kind it can scarcely be
placed elsewhere. The representatives of the group are separated
from those of the preceding series by their property of forming
52 BLOWPIPE PRACTICE.
uncoloured glasses with the blowpipe fluxes ; and from those of the
next series by their non-alkaline character. With reference purely to
blowpipe characters, it would perhaps be a more satisfactory arrange-
ment if magnesium were also referred to this group, the other
metals of Group 6 and those of Group 7 being placed together in a
single group under the name of F lame-colour ers. Keeping, however,
to the present distribution, it may be pointed out that aluminum
compounds are distinguished from those of the associated metals by
not forming an opaque glass with borax, and by the blue colour
assumed after ignition with nitrate of cobalt. Compounds of the
other metals belonging to the group are of comparatively rare
occurrence.
(40) Tantalum. — Occurs only in an oxidized condition as tantalic
acid (Ta205) commonly associated with columbic or niobic acid (Nb205)
and combined with iron oxide and other bases, in a few minerals of
exceptional occurrence. Tantalic acid becomes pale yellowish on
ignition, but resumes its white colour 011 cooling, and remains
infusible. After treatment with cobalt-solution it becomes pale flesh-
red. "With carb. soda it dissolves with effervescence, but is not
reduced. With borax, it dissolves easily, the saturated glass
becoming opaque on cooling or by flaming. With phosphor-salt it
forms a permanently clear bead. Its presence in minerals cannot be
safely detected by the blowpipe alone.
(41) Aluminum. — Occurs in nature as a fluoride (in cryolite, &c.),
but essentially as an oxide, APO3. The latter compound occurs
alone and in a hydrated condition (corundum, diaspore, gibbsite) ;
and in combination with magnesia and other bases as the electro-
negative principle of the small group of aluminates. It occurs also,
and more frequently, as a base, in various silicates, phosphates, and
sulphates. Exceptionally, also, as an arseniate ; and in combination
with an organic acid in the mineral mellite. Alumina presents the
following blowpipe reactions : (1) Per se, it is infusible and unchanged.
(2) Moistened with nitrate of cobalt, and ignited, it assumes, on
cooling, a fine blue colour. The reaction is exhibited by all aluminous
silicates, phosphates, &c., which are free from iron oxides or other
strongly coloured bases (Seepage 12.) (3) Alumina is not attacked
by carb. soda. (4) It is very slowly dissolved by borax and phos-
phor-salt, forming colorless, permanently clear beads. (5) It is
REACTIONS. 53
dissolved, in fine powder, by fusion in a platinum spoon with five
or six partsof bisulphate of potash (page 20). The aqueous solution
of the fused mass yields a white precipitate (soluble in caustic potash)
with ammonia. Silicates resist this treatment, but in fine powder
many are soluble in hydrochloric acid, and nearly all may be ren-
dered soluble by previous fusion with a mixture of carb. soda and
borax. The solution (with slight addition of nitric acid) must be
evaporated slowly to dryness, the residuum moistened with a couple
of drops of hydrochloric acid, water added, and the clear supernatant
liquid decanted or filtered from the insoluble silica. If the precipitate
formed in the filtrate by ammonia be brown in colour, it must be
separated and boiled with caustic potash. This will take up any
alumina that may be present, leaving Fe203 undissolved.
(42) (rlucinum, or, Beryllium. — Occurs only in an oxidized con-
dition, BeO, as a base in a small number of silicates (Phenakite,
Beryl, Euclase, &c.), and in a single alurninate (Chrysoberyl).
Glucina is infusible per se, and is not dissolved by carb. soda.
With cobalt solution it becomes pale bluish-grey; with borax and
phosphor-salt it dissolves more or less readily, the saturated glass
becoming opaque on cooling or when flamed. When glucina is com-
bined with other bodies, its blowpipe reactions are not sufficient for
its detection.
(43) Zirconium. — Occurs only oxidized, as ZrO2 in combination
with silica and various bases in a small number of minerals. The
zircon (ZrO2, SiO'2), distinguished chiefly by its hardness, high sp.
gr. (=4-2-4'8), Tetragonal crystallization, and infusibility, is the
only representative species of tolerably common occurrence. Zir-
conia when ignited, glows with more than ordinary brightness, but
remains unfused. After treatment with cobalt solution, it assumes
a dull violet tinge. It is not dissolved by carb. soda, but dissolves
freely in borax and phosphor-salt, forming a colourless glass which on
saturation becomes opaque on cooling or by flaming. Zircon and
other silicates in which zirconia is present become decomposed by
fusion in tine powder with carbonate of soda, and they are then
soluble or partially soluble in hydrochloric acid. The dilute solution,
as first pointed out by BRUSH, imparts an orange-yellow or reddish-
brown colour to turmeric paper, seen most distinctly as the paper
dries.
54 BLOWPIPE PRACTICE.
(44) Yttrium. — This rare metal (almost always associated with
Erbium) occurs in the mineral of Yttrocerite as a fluoride; but in
general it is found in an oxidized condition (YO) as a base in cer-
tain silicates, titanates, tantalates, niobates and phosphates, all of
more or less exceptional occurrence. The blowpipe reactions of
yttria agree in all essential respects with those of glucina. It is
thus infusible per se, and also with carb. soda ; but soluble in borax
and phosphor-salt, the saturated glass becoming opaque by flaming
or on cooling. Practically, its presence in minerals escapes detection
by the blowpipe.
VI. ALKALINE EARTH-METALS.
This group includes magnesium, calcium, strontium, and barium.
The two first by the insolubility of their oxides (before the blowpipe)
in carb. soda, are allied to the metals of the preceding group, whilst
the general solubility of strontium and barium compounds in that
reagent, connects the latter metals with those of Group VTI. The
carbonates, sulphates, fluorides, &c., of all the representatives of the
group, react alkaline after strong ignition, and thus restore the blue
colour of reddened litmus-paper ; but in other compounds (silicates,
&c.), the reaction is less clearly marked or is not observable. All
the oxides belonging to this group dissolve freely in borax and
phosphor-salt, forming clear glasses which on saturation become
opaque by flaming or when cold. Magnesium compounds impart no
colour to the flame ; compounds containing calcium and strontium
colour the flame red or crimson, and barium compounds communicate
to it an apple-green coloration.
(45) Magnesium— Occ\.\rs, though rarely, as a chloride, and still more
rarely as a fluoride ; very abundantly, on the other hand, as an oxide,
magnesia, MgO. This compound, though occuring alone in Peiiclase,
arid as a hydrate in Brucite, is chiefly met with as a base in various
alumiriates, silicates, sulphates, carbonates, borates, phosphates and
arseniates. Magmsia is infusible per se, and insoluble in carb. soda.
After ignition with nitrate of cobalt it assumes on cooling a pale flesh -
red colour. This reaction is manifested by magnesium carbonates,
silicates, &c., in the absence of iron or other colouring oxides, but in
many cases it is not very distinct. Magnesia does not colour the
blowpipe-flame, and its compounds, when ignited in a Bunsen-burner,
give no spectrum bands. With borax and phosphor-salt it dissolves
REACTIONS. 55
very readily, the saturated glass becoming opaque on cooling or when
flamed. The non-coloration of the flame and the reaction with nitrate
of cobalt generally serve to distinguish magnesian compounds, except
in the case of certain silicates. In these, and in other doubtful cases,
the test-substance, in fine powder, may be dissolved in a small quan-
tity of hydrochloric acid in a porcelain capsule over the spirit lamp
or Bunsen flame ; or, if insoluble in acids, it may be rendered soluble
by previous fusion with a mixture of carb. soda and borax. The
fusion is best performed in a paper cylinder (according to Plattner's
method), the cylinder being made and filled as directed in the case
of the lead cylinder on. page 32. The solution is then to be diluted,
a drop of nitric acid added, the whole evaporated to dryness (to sepa-
rate silica), the residuum re -moistened with hydrochloric acid, distilled
water added, and the solution filtered. In the filtrate, APO and
Fe2O3, if present, are thrown down by ammonia in slight excess ;
lime is next precipitated by oxalic acid or oxalate of ammonia ; and
finally the magnesia is separated by some dissolved phosphor-salt.
Care of course must be taken in each case to see that the precipitation
be complete.
(46) Calcium. — Occurs frequently as a fluoride, and occasionally as
a chloride ; but principally in an oxidized condition (CaO) as a base in
silicates, carbonates, sulphates, phosphates and other oxygen- com-
pounds. Lime glows strongly on ignition, and imparts to the flame-
border a distinct red colour, but this is less intense than the crimson
coloration produced by strontium and lithium compounds. The
characteristic bands in its spectrum are two in number — an orange,
red band (a little farther from the sodium line than the orange
strontium band), and a clear green band.* This flame reaction is
* In these examinations, a small, direct-vision spectroscope— such as Browning's pocket
spectroscope with attached scale and extra prism— will be found most suitable. By a little
practice, the student will readily recognize the positions of the red and orange lines, without
the assistancs of the scale, by their relative distance from the sodium line. A small fragment
of lepidolite will give the sodium and lithium lines very distinctly. Strontianite, and also
celestine, after a short exposure to the flame, give the orange, red, and blue lines characteristic
of strontium ; heavy spar and witherite, the characteristic barium bands ; and fluor-spar,
gypsum, calcite, &c., the red and green calcium lines. The effect is heightened by moistening
the calcined test-matter with a drop of hydrochloric acid, but as regards the above (and various
other) minerals, the distinctive lines come out very vividly by a sufficiently prolonged ignition
of the substance per se. The small sharp-edged fragment is conveniently held in the platinum-
tipped forceps, and these can be fixed at the proper height by thrusting their opposite ends
across the stem of one of the ordinary wire supports used in spectroscope examinations.
56 BLOWPIPE PRACTICE.
given by carbonates and sulphates, as well as by fluor spar, after
prolonged ignition in the Bimseii flame, but as a rule it is best
obtained by moistening the test-substance with hydrochloric acid.
Per se, lime is infusible. It is not dissolved by carb. soda, but dis-
solves readily by fusion with borax and phosphor-salt, the saturated
glasses becoming opaque by flaming or on cooling. With nitrate of
cobalt a dark-grey coloration is obtained. For the detection of lime
in silicates, see under Magnesium, No. 45.
(47) Strontium. — Occurs only, among natural compounds, in an
oxidized condition, as SrO, combined with sulphuric acid and with
carbonic acid ; more rarely with silica. Both the sulphate and car-
bonate become caustic on ignition, and then give the crimson flame-
coloration and other reactions of pure strontia, — dissolving, like the
latter, very readily and completely in carbonate of soda, a character
by which strontium and barium compounds (with those of the alkali
metals proper) are at once distinguished from other alkaline earths.
With borax and phosphor-salt strontia dissolves freely, the colorless
glass becoming opaque (if sufficiently saturated) on cooling or when
flamed. After ignition with nitrate of cobalt, strontia becomes dark-
grey or black. In the strontium spectrum the distinctive lines
comprise (1) a broad orange-red line, quite close to the sodium line,
(2), a group of several crimson lines, and (3) a single blue line. A
small fragment of strontianite or celestine shews these lines very
distinctly after a short exposure to the edge of the Bunsen flame. If
a strontium compound be fused on platinum wire with chloride of
barium, the crimson flame -coloration is destroyed. By this character
— as well as by the spectrum — strontium compounds are readily
distinguished from those of lithium. (See Appendix, No. 4.)
(48) Barium.— Occurs in nature in an oxidized condition only,
and chiefly as a sulphate and carbonate, more rarely as a silicate.
Present also in some of the naturally-occurring oxides of manganese.
Baryta dissolves entirely in carb, soda, and resembles strontia in its
other blowpipe reactions, except as regards the coloration of the
flame and the reaction with nitrate of cobalt. It communicates to
the flame-border an apple-green or yellowish-green colour, and be-
comes reddish-brown after treatment with the cobalt solution (page
12), but the latter reaction is of little moment. The spectrum of
REACTIONS. 57
barium compounds is essentially characterized by a group of green
lines, four or five in number, of which two are especially vivid and
distinct; with a line or two, often ill-defined, in the orange and
yellow, and one or two more or less indistinct lines near the commence-
ment of the blue, the whole at nearly equal distances apart. The
group of green lines is the characteristic portion of the spectrum. In
the calcium or lime spectrum there is only a single well-pronounced
green or yellowish-green line, whilst the spectra of Sr, Na, Li, and K,
show no green lines. See also Appendix, Nos. 1 and 2.
VII. ALKALI METALS.
This group includes Lithium, Sodium, Potassium, and Ammonium.
Compounds of these alkali metals much resemble strontium and
barium compounds in their general blowpipe reactions. They impart
a colour to the flame, and dissolve readily, by fusion, in carb. soda.
The flame coloration of lithium compounds is crimson ; of sodium
compounds, yellow ; of potassium compounds, clear violet ; of ammo-
nium compounds, pale or dull green.
(49) Lithium. — This metal as an essential mineral-component
occurs only in an oxidized condition (Li'O) in a few silicates and
phosphates ; but in minute quantities it appears to be widely dis-
tributed throughout nature. The presence of lithia in most corn-
pounds is readily detected by the crimson coloration imparted to the
blowpipe flame or that of the Bunsen burner, especially on pro-
longed ignition. When lithia is merely present, however, as an
accidental or inessential constituent, the flame-coloration is best
brought out by moistening the test-matter in powder with a drop or
two of hydrochloric acid. The mixtures of bisulphate of potash and
fluor-spar, or gypsum and fluor-spar, recommended in books for this
purpose, often bring out by themselves a vivid red coloration. By
fusion with chloride of barium, the intensity of the lithium flame is
increased, whereas by this treatment the red flame of strontium is
destroyed (see Appendix, No. 4). The spectrum of lithium is also
exceedingly characteristic. It consists practically of a single crim-
son line, much farther from the sodium line than the characteristic
orange-red line of strontium, or the red calcium line. Most
examples of lepidolite give the lithium and sodium lines together.
58 BLOWPIPE PRACTICE.
(50) Sodium or Natrium. — Widely distributed as a chloride, and
occurring also as a fluoride. Present also abundantly in an oxidized
condition (Na2O) in various, silicates, sulphates, and carbonates, and
in the nitrate soda- nitre. Distinguished very readily in most cases
by the strong yellow coloration which its compounds impart to the
Bunsen and blowpipe flame. Its spectrum consists of a single yellow
line (as sesn in ordinary spectroscopes) corresponding in position with
the line (or double line) D of the solar spectrum. This yellow line
is exceedingly characteristic ; and its very constant presence in spectra,
generally, serves as a convenient index to the position of other lines,
as those of calcium, strontium, &c. The yellow flame-coloration is
completely hidden if viewed through a deep-blue glass.
(51) Potassium or Kalium. — Occurs as a chloride ; but more com-
monly in an oxidized condition (K20) as a sulphate and nitrate, and in
various (chiefly aluminous) silicates. Potash (if perfectly free from
soda) imparts to the outer flame a clear violet tint, but this coloration
is masked or rendered more or less invisible by the least trace of soda
or of any sodium compound, and also as a rule by other flame-colouring
bodies. If the flame bs viewed however, as first shewn by Cartmell,
through a deep-blue glass or a solution of indigo, the yellow coloration
due to sodium becomes entirely obliterated, and the potash-flame
exhibits a bluish-red colour. The indigo-solution (1 part indigo,
8 concentrated sulphuric acid, 1500 water) is best contained in a
prism-shaped or wedge-shaped bottle, so that different thicknesses
may be conveniently brought between the eye and the flame.
Cornwall has recommended a solution of permanganate of potash in
place of the indigo solution. When the potash flame is obscured by
lithium, it will be rendered visible, according to Merz, if viewed
through a green glass, the lithium flame becoming then obliterated.
A good deal depends, however, 011 the shade of colour of these glasses
and solutions, and the results are not always entirely satisfactory.
Whenever therefore recourse can be had to the spectroscope, the
latter should always be employed. The potassium spectrum consists
essentially of two lines, far apart — a red line, almost at the commence-
ment of the normal spectrum (it coincides, practically, with the solar
line A), and a violet line near the other extremity of the spectrum
proper. The latter line, however, is not generally visible, and in small
spectroscopes the two lines can rarely be seen together. The red
REACTIONS. 59
line is the characteristic one. It lies about (but not quite) as far
from the red lithium-line as this lies f<*om the sodium-line. Starting
therefore from the latter, the characteristic orange and red spectrum
lines of the common alkaline and earthy bodies succeed each other in
the following order : (Na) — Sr — Oa — Sr (group of lines) — Li — K :
one of the red Sr-lines coinciding with the solitary Li-line.* If the
student be uncertain, at any time, as regards the red K-line, he
should insert into the edge of the Bunsen flame a small scale of
lepidolite (or other lithium- containing body), when the relative posi-
tions of the two will at once become apparent ; or, if his spectroscope
be fitted with an extra prism, he can, of course, examine the two
spectra separately. The nitrate, and the natural sulphates and
chlorides (as well as the ordinary potassic salts of the laboratory,
phosphates, bromides. &c.), give the reaction very distinctly, but it is
not always produced directly by natural silicates. To detect potash
in the latter, a small portion of the silicate, in fine powder, must be
fused on a loop of stout platinum wire with a mixture of carb. soda
and borax, and the fused bead (crushed to powder) must be boiled
with a few drops of hydrochloric acid. The solution, evaporated
nearly to dryness, or a small portion of the pasty mass, may then be
examined by the spectroscope. The presence of sodium does not
interfere with the production of the red potassium-line, but the
supporting wire should be kept, as a rule, just at the edge of the
Bunsen-flame, and the observations should be made in a darkened
room.
(52) Ammonium. — Occurs in Inorganic Nature chiefly as a
chloride ; more rarely in an oxidized condition as, a sulphate and
borate. Accidentally present also in many bog iron ores and other
minerals which contain traces of intermixed organic matter. Its
presence is recognized more or less readily by the odour evolved on
moderate ignition, especially if the substance, mixed with dry carb.
soda, be ignited in a test-tube. A slip of red litmus-paper, slightly
moistened and placed at the top of the tube, will be rendered blue by
the evolved vapours ; and these will also manifest themselves in white
fumes if a glass rod moistened with hydrochloric acid be brought
* The ash of a cigar or of ordinary tobacco, if moistened with hydrochloric acid, will show
the green and red calcium lines and the red K-line very distinctly. The lithium-line is also
shewn by some kinds of tobacco.
60 BLOWPIPE PRACTICE.
over the opening of the tube. Most ammonium compounds impart
a feeble blueish-green or brownish-green colour to the flame, but
none give a distinctive spectrum.
§6.
PLAN OF ANALYSIS.
In the examination of a mineral substance with a view to determine
its general nature by the blowpipe — aided by such liquid reagents
and processes as are available in blowpipe practice — it is advisable, in
the first place, to determine the electro-negative element or compound
in the substance (or, in other words, to ascertain the chemical group
to which the substance belongs), and afterwards to determine the
base or bases that may be present in it.
The methods of Blowpipe Analysis usually followed, although well
adapted to convey a knowledge of the special reactions of bodies,
have two essential defects : they draw no line of separation between
electro-negative substances and bases, but mix up the two together
in a loose and confusing manner ; and they exact the performance
of a great number of experiments, by which many substances are
detected over and over again, whilst others may easily escape detec-
tion altogether.
In the plan now proposed, these defects are in a great measure
remedied, and a knowledge of the chemical nature of an unknown
mineral — so far as this epi be obtained by the Blowpipe— is arrived
at without unnecessary trouble or delay. If the electro-negative
principle in the substance be not detected by one or the other of the
eight easily and rapidly performed experiments given under the first
section of the scheme, the substance— unless it be a telluride, tanta-
late or other rare compound, properly omitted from consideration in
an outline of the present character — will be either a simple basic-
oxide or metal, and its true nature will be revealed in the examina-
tion for bases, as given under TABLE B. It will, of course, be
understood, that, as a rule, the entire series of experiments for the
detection of electro-negative bodies need not be carried out. Sulphates,
for example, will be recognized by the first experiment, carbonates
and silicates bv the second, and so on as regards representatives of
other groups. Except, therefore, in certain rare cases indicated in
the text (as in the combination of a phosphate and fluoride, &c.), it
PLAN OF ANALYSIS.
61
will only be necessary to continue the experiments until the chemical
group to which the substance essentially belongs has been ascertained.
The base or bases, present in the substance, may then at once be
sought for.
A.— DETECTION OF ELECTRO-NEGATIVE BODIES.
EXPERIMENTS.
RESULTS MORE ESPECIALLY
SUBSTANCES INDICATED.
TO BE LOOKED FOR.
1. Fuse the test-sub-
(1) Emission of arseni-
(1) As., Arsenides, Ar-
stance, in powder, with
cal odour.
seniates.
carb. soda (and a small
addition of borax) in R.
(2) Emission of copious
fumes, and deposition of
(1 and 3) AaS., As2S3,
Stilpharsenites.
F. on charcoal.
dense white coating on
(2 and 3) Sb2S3; Sul-
Moisten fused mass,
the charcoal.
phantimonites.
and place on lead test-
(3) Formation of "he-
(3) 8. Sulphides, Sul-
paper or silver-foil.
par," or alkaline sulph-
phates, also the rare
ide.
Selenides.
N. B.-If the fa sion be effected
by a gas flame, the gas should
Other results (if any) such
See special reactions § 5, for
be tested previously for pres-
ence of sulphur. 'See under
as reduction to metal, yellow
coating on charcoal, &c. , may
distinctive and confirmatory
characters.
"Sulphur "ing 5.
be noted down for after refer-
ence.
2. Fuse solid particle
of test-substance with
(1) Very slow solution,
with formation of silica-
(1) Silica, Silicates
generally.
(previously fused) bead of
phosphor-salt on plati-
num wire.
skeleton or opalescent
bead.
(2) Rapid solution, ac-
companied throughout
by effervescence.
(2) Carbonates (also
bodies which evolve
oxygen, as MnO2, Bichro-
mates, Chlorates, &c. ).
Other results (as rapid solu-
Confirmatory tests.— For SiO2,
tion without effervescence,
fuse with carb. soda. Heat, in
&e.), may be noted down, but
test-tube, with HC acid (for
are not to be taken into ac-
gelatinization, &c.). For Car-
count here.
bonates, warm, in test-tube,
with dilute HC acid (for effer-
vesence).
3. Fuse test-substance
Rich azure blue flame.
Chlorides.
in powder with phosphor-
salt and copper oxide on
plat, wire, or with phos-
phor-salt alone on copper
NOTE. — If a blue and green,
or an intensely vivid green
flame be produced, Br. and I
may be suspected, but natural
Also, chloro-phosphates (a»
pyromorphite, many apatites,
&c.) Confirm by Experiment 4.
wire.
Bromides and Iodides are of
very rare occurrence. Test
with (dry) bisulphate of pot-
ash in closed tube over Bun-
sen flame (for yellow or violet
fumes).
62 BLOWPIPE PRACTICE.
DETECTION OF ELECTRO-NEGATIVE BODIES-(CWtm<e<?).
EXPERIMENTS.
RESULTS MORE ESPECIALLY
TO BE LOOKED FOR. •
SUBSTANCES INDICATED
4. Boil the substance,
in fine powder, with a
few drops of nitric acid
in a test,tube. Half -till
the tube with water, drop
into the solution a frag
ment of amm. molybdate,
and warm gently.
A canary-yellow pre-
cipitate.
Phosphates.
NOTE. — Most phosphates,
especially if moistened with
sulphuric acid, impart a green
Inge to the flame.
Many natural phosphates are
combined with chlorides or
iuorldes, or with both. 01., if
^resent, will have been detected
>y Expt. 3 ; Fl. must besought
for by Expt. 6.
5. Warm the test-sub-
stance, in powder, with a
few drops of sulphuric
acid, add a little alcohol,
stir and inflame the mix-
ture.
(1) A deep-green solu-
tion.
(2) A rich blue solu-
tion.
(3) A green coloration
of the flame.
NOTE.— A green flame is pro-
duced by tnost borates per se,
in all, by moistening the test-
substance with sulphuric aoid,
or with glycerine. Phosphates,
however, produce the same re-
action when thus treated, but'
do not give a green flame with
alcohol.
(1) Chromates.
(2) Molybdates,
(3) Borates, also ' ' Boro-
Silicates.'' ,
NOTE. — Small portions of
B2O3 in silicates, &c., m»y
escape detection by this Expt.
but the object of the present
scheme is not to detect minute
or inessential components, but
to determine the chemical
group to which the test-sub-
stance may belong. See under
Reactions, § 5.
6. Heat the substance,
in powder, with a few
drops of strong sulphuric
acid in a narrow test-tube.
(1) Corrosion of inside
of tube. (Wash out
thoroughly, and dry be-
fore coming to conclu-
sion. )
(2) Evolution of ruddy
(nitrous) fumes.
(1) Fluorides, also com-
binations of Fluorides
and Phosphates (see under
Expt. 4 above).
(2) Nitrates.
Confirmatory test for nitrates.
— Ignite on charcoal (for defla-
grescence),
7. Fuse teat-substance,
in fine powder, with about
3 parts of oarb. soda and
2 nitre inaplatinum spoon
or loop of platinum wire.
Dissolve resulting soluble
matters in hot water;
decant clear solutipn into
a small porcelain capsule,
add a few drops of hydro-
chloric acid, and place in
the solution a piece of
zinc.
A dark-blue coloration.
NOTE. - - Molybdenum com-
pounds when thus treated maj
also produce a blue coloration
at first, but this, on standing,
becomes rapidly dark brown.
(1) Tungstates.
If much MnO be present (as
in Wolfram), the solution will
at first be green, but this dis-
appears rapidly on heating,
and the solution beoom< s
nearly colorless and then deen
indigo-blue.
PLAN OP ANALYSIS.
DETECTION OF ELECTRO-NEGATIVE BODIES— (Continued).
63
EXPERIMENTS.
RESULTS MOKE ESPECIALLY
TO BE LOOKED FOR;
SUBSTANCES INDICATED.
8. Fuse test-substance,
in fine powder, with 5 or
6 parts of bisulphate pot-
ash (added successively^
in platinum spoon or wire
loop. Dissolve out in
slightly warm water,
decant and boil.
A white or pale-yel-
lowish precipitate', chang-
ing to a violet or amethy-
stine colour if Warmed
with hydrochloric acid
and a piece of 2inc or
tin-foil. (See page 51.)
Titanic Acid.
Titaniates.
Confirmatory test. — Fuse a
portion of the principitate
with phosphor-salt on plat,
wire. See Reactions, § 6.
B.— DETECTION OF BASES.
In many minerals, the so-called base — -lead, for example, in sul-
phide of lead, copper in red or black oxide of copper, baryta in car-
bonate of baryta, and so forth — may be easily recognized by the use
of the blowpipe. This is especially the case, when the base consists
of a single and easily reducible metal or metallic oxide, such as silver,
lead, copper, tin, &c. ; or where it imparts a colour to borax or other
reagent, as in the case of copper, iron, cobalt, nickel, manganese, &c. ;
or where it forms a deposit on charcoal, communicates a colour to
the flame, or exhibits other characteristic reactions. Even when
several bodies of this kind are present, their recognition, as a general
rule, is easily effected. Earthy and alkaline bases, when in the form
of carbonates, sulphates, phosphates, fluorides, &c., can also be made
out, in general, without difficulty, unless several happen to be present
together, in which case it is not always possible, by the simple aid of
the blowpipe, to distinguish them individually. When these bases
are combined with silica, on the other hand, the blowpipe alone is
rarely sufficient for their detection. This, however, so far as practical
purposes are concerned, is of little consequence, as no economic valuer
in silicates of this character, is dependent on the base. In general
cases, four experiments only will be required. These comprise :
Testing for water by ignition in the bulb-tube ; fusion or ignition of
the substance per se ; fusion with carb. soda ; and fusion with borax.
It will thus be seen that, in many oases, the nature of the base will
be sufficiently revealed by the reactions which ensue during the
determination of the electro-negative character of the substance.
BLOWPIPE PRACTICE.
EXPERIMENTS.
RESULTS MORE ESPFCIALLY TO
BE LOOKED FOR.
SUBSTANCES INDICATED.
1. Ignite in bulb-tube.
( 1 ) Presence of moisture
(2) Assumption of dark
NoTE.-This experiment may ! co]our and magnetism.
be omitted as a rule in the case
of minerals of metallic aspect.
Other results (if any) may be
| disregarded.
1. Water.
Test with blue and red litmus
papers.
2. Iron, probably as FeO.
2. Ignite or fuse per se
in platinum forceps, or, if
metallic, on charcoal.
3. Fuse (after thorough
roasting, if necessary)
with carb, soda and a little
borax on charcoal ; or, if
the substance present a
non -metallic aspect, on
platinum wire.
( 1 ) Coloration of flame :
« Red flame; 1* Yellowflame;
lc Green flame ; 1<* Blue flame ;
Violet flame.
(2) Ring-deposit on char-
coal :
2« White dep. ; 2& Red-brown
dep. ; 2c Yellow dep.
(3) Assumption of mag-
netism.
(4) Assumption of caus-
ticity. (Page 9.)
Other results (if any) may be
disregarded.
(1) White or yellow
ring-deposit on charcoal.
(2) Reduced metal :
2* Fusible, non-oxidizable
globule; 26Infus., non-ox, par-
ticles ; i;c Infusible, oxidizable,
magnetic particles; 2d Fusible,
oxid., mm-volatile globules ; 2«
Fusible, volatilizable globules.
(3) A green-blue tur-
quoise enamel.
(4) Complete solution
(with absorption, if on
charcoal).
(l)a Lithia, strontia,
lime.
(I)6 Soda
(l)c Copper, antimony,
zinc, molybdenum, baryta,
ammonia.
ld Lead. (Also CuCl,
&c.)
1« Potash.
See Reactions, § 5, and Ad-
dendum to Table B, below The
student must remember that
certain electro-negative bodies,
S, P2O&. B2()8, &e., also give col-
oured flames.
2a Antimony (yellowish,
hot); arsenic ; zinc (yellow
and phosphorescent, hot);
molybdenum (yellowish,
hot) ; tin (very slight).
26 Cadmium.
2C Bismuth ; lead ; zinc
(whilst hot).
See Addendum, below.
*3. Iron.
4. Alkaline earths
(CaO. &c.) in carbonates,
sulphates, fluorides, &c.
(1) See under Expt. 2;
also the Addendum below.
(2)« Gold ; Silver.
(2)5 Platinum.
(2)c Iron, Nickel, Cobalt
2d Copper ; Tin (practi-
cally).
2e Bismuth ; Lead ; An-
timony.
(3) Manganese.
(4) Baryta ; Strontia ;
Alkalies.
See Addendum, below.
PLAN OF ANALYSIS.
65
DETECTION OF BASKS -(Confined).
EXPERIMENTS.
4. Fuse with borax on
platinum wire (after
thorough roasting, if ne-
cessary).
5. Additional experi-
ments— (as ignition with
cobalt solution ; testing
for Hg. with reducing
agents in closed tube ; cu-
pellation, &c. , ) if thought
necessary by physical
characters of the test-
substance, or by indica-
tions resulting from the
above blowpipe trials.
RESULTS MORE ESPECIALLY to
BE LOOKED FOR.
(1) A coloured bead
which becomes turbid or
opaque (from reduction or
partial reduction) in the
RF.
(2) A coloured bead, not
becoming opaque in RF.
(3) A colourless bead,
not affected by flaming.
(4) A colourless bead
which becomes opaque on
saturation or by naming.
SUBSTANCES INDICATED.
(1) Copper ; Nickel ;
Cerium ; Uranium (the
glass becomesblackinRF).
Also Molydenum (to
some e x tent ) ,Tungstenum
and Titanium ; but these
metals occur mostly in
minerals as oxidized elec-
tro-negatives, and thua
come under detection in
TABLE A.
(2> Manganese ; Chro-
mium (see Table A) ; Iron ;
Cobalt.
(3) Alumina ; Tin oxide
(to some extent). Both
very slowly attacked.
(4) Zirconia ; Glucina ;
Yttria ; Zinc oxide ; Alka-
line earths (MgO, CaO,
etc.); Alkalies.
ADDENDUM TO TABLE B.
A Classification, according to their Blowpipe Characters, of the more commonly
occurring Mineral Bases,
SECTION 1. — GIVING per se, OR WITH CARD. SODA, ON CHARCOAL,
METALLIC GLOBULES OR METALLIC GRAINS.
Group 1. — Yielding malleable metallic globules, without deposit on
the charcoal.
6
66 BLOWPIPE PRACTICE.
Gold. Silver. Copper.
Gold is insoluble in the fluxes. Silver is not oxidized per se, but
retains a bright surface after exposure to an oxidating flame. Copper
becomes encrusted on cooling with a black coating. It imparts a
green colour to the flame-border ; and forms strongly coloured glasses
with borax and phosphor-salt : (green (hot), blue (cold), in O F :
red-brown, opaque, in R F : see above). Gold and silver may be
separated from copper, &c., by fusion with lead, and subsequent
cupellation. If gold and silver be present together, the bead is
generally more or less white. By fusing it in a small platinum-
spoon with bisulphate of potash, the silver dissolves, and the surface
of the globule becomes yellow. If the globule be flattened out into
a disc on the anvil, before treatment with bisulphate of potash, tha
silver is more rapidly extracted. The sulphate of silver must be
removed by treating the spoon, in a porcelain or platinum capsule,
with a small quantity of water, over the spirit-lamp. By evaporation,
and fusion of the residuum with carb. soda on charcoal, metallic silver
can be again obtained.
Group 2. — Yielding infusible metallic grains, without deposit on the
charcoal.
Platinum. Iron. Nickel. Cobalt. Molybdenum. Tungstenum.
Platinum is not attacked by the blowpipe fluxes. Iron, Nickel, and
Cobalt, or their oxides, are readily dissolved by fusion with borax or
phosphor-salt, producing a coloured glass. (See under " Borax," pages
13, 14, above.) These metals are also magnetic. As a general rale
if a substance become attractable by the magnet after exposure to the
blowpipe, the presence of iron may be inferred, cobalt and nickel com-
pounds being comparatively rare. The presence of cobalt is readily
detected by the rich blue colour of the borax and phosphor-salt glasses,
in both an oxidating and reducing flame ; but if much iron be present
also, the glass is bluish-green. With borax in the R F, nickel com-
pounds give reduced metal, and the glass becomes gray and troubled.
Molybdenum and Tungstenum give non-magnetic grains of reduced
metal. They are commonly present in minerals as the electro-nega-
tive principle, and their presence is best detected by the method given
under Experiment 7, Table A, above.
PLAN OF ANALYSIS* 67
Group 3. — -Yielding metallic globules, with white or yellow deposit
on the charcoal.
Tin. Lead. Bismuth. Antimony.
Tin and Lead give malleable globules.* The sublimate formed by
tin is white, small in quantity, and deposited on, and immediately
around, the globuler The lead sublimate is yellow, and more or less
copious. Bismuth and Antimony give brittle globules. The bismuth
sublimate is dark yellow ; the antimony sublimate, white, and very
abundant. Lead imparts a clear blue colour to the flame-border ;
antimony, a greenish tint. As a general rule, a yellow deposit on the
charcoal may be regarded as indicative of the presence of lead; whilst,
the emission of copious fumes, and deposition of a white coating on the
charcoal, may be safely considered to indicate antimony. The coating
or sublimate formed by zinc (see below), although white when cold,
is lemon-yellow whilst hot. The rare metal, tellurium, closely resem-
bles antimony in its reactions, but if warmed with concentrated sul-
phuric acid, it forms a reddish-purple solution.
NOTE. — An excellent method of distinguishing the blowpipe-subli-
mates of lead, bismuth, antimony, and also cadmium, has been
recently discovered by Dr. Eugene Haanel, of Victoria College,
Cobourg (Ontario). Moistened with a drop of hydriodic acid, and
ignited, the lead sublimate becomes bright canary-yellow; the bismuth
sublimate, chocolate-brown ; the antimony sublimate, bright red ; and
the cadmium sublimate, white. The hydriodic acid is obtained by
steeping iodine in water, and passing through the liquid a current of
sulphuretted hydrogen until it becomes clear. The reactions pro-
duced by this method are remarkably distinct.
SECTION 2. — REDUCIBLE, BUT YIELDING NO METAL ON CHARCOAL.
(This arises from the rapid volatilization of the reduced metal.)
Group 1. — Volatilizing without odour, and without formation of a
deposit on the charcoal.
Mercury.
For the proper detection of this metal, a small portion of the test-
substance in powder must be mixed with some previously dried carb.
* See in the Appendix, No. 21, the striking reaction manifested by alloys of these metals.
68 BLOWPIPE PRACTICE.
soda, and the mixture strongly ignited at the bottom of a small tube
or narrow flask. If mercury be present, a gray sublimate will be
formed. This may be collected by friction with a wire, &c., into
small metallic globules, and poured out of the tube. If some iron
filings be mixed with the carb. soda, the mercurial sublimate is more
readily obtained.
Group 2. — Volatilizing without odour, but forming a deposit on the
charcoal.
Cadmium. Zinc.
The deposit produced by cadmium is dark yellowish-brown or red-
dish-brown. That produced by zinc is lemon-yellow and phosphor-
escent whilst hot, and white when cold. If moistened with a drop
of nitrate of cobalt and ignited, it becomes bright green.*
Group 3. — Volatilizing with strong odour of garlic.
Arsenic (more commonly present in minerals as an electro-negative
body. See Table A, above).
The alliaceous or garlic like odour is most readily developed when
the test-matter is mixed with some carb. soda, or other reducing flux,
and exposed on charcoal to the action of a reducing flame.
The presence of arsenic may also be proved as follows : (1)
By roasting a. fragment of the substance in an open glass tube,
when minute octahedrons of arsenious acid (easily recognized by their
triangular faces if examined by a common lens) will be deposited at
the upper end of the tube ; and (2), by igniting the test-substance,
mixed with some dry oxalate of potash or cyanide of potassium, at
the bottom of a small flask or closed tube, when a dark, shining subli-
mate of metallic arsenic will be produced. Without the reducing
flux, a yellow or yellowish-red sublimate of arsenical sulphide might
be formed in certain cases.
SECTION 3. — NOT REDUCIBLE BEFORE THE BLOWPIPE.
Group 1. — Imparting a colour to borax.
Manganese. Chromium. Titanium. (The two latter are com-
tnonly present in minerals as electro-negative bodies.)
* In testing a substance supposed to contain cadmium, a little chalk-powder or bone ash may
lie rubbed over the surface of the charcoal. If cadmium be present, its reddish-brown subli-
mate (CdO) is then more readily seen.
PLAN OF ANALYSIS. 69
Manganese compounds impart, before an oxidating flame, a violet
colour to borax ; Chromium compounds, a clear green colour. (See
also under " Carbonate of Soda," page 15, above.) Titanium com-
pounds form, with borax in the E- F, a brownish-amethystine glass,
which becomes light blue and opaque by naming. The presence of
titanium in minerals is most readily detected by fusing the substance
in very fine powder with 3 or 4 parts of carb. soda in a platinum spoon,
dissolving the fused mass in hydrochloric acid, diluting slightly, and
then boiling with a slip of tin or zinc. The solution, if titanium be
present, will gradually assume an amethystine tint. Or, the sub-
stance, in fine powder, may be fused with bisulphate of potash in suc-
cessive portions. The titanic acid by this treatment becomes soluble
in water, from which it may be precipitated as a white or slightly
yellowish powder by boiling. The precipitate can then be fused
before the blowpipe in a reducing flame with some phosphor-salt, when
a violet-coloured or amethystine bead will result. If iron be present
in the substance, a drop or two of hydrochloric acid should be added
to the solution before the precipitation of the titanic acid.
The rare metals, cerium, uranium, &c., belong also to this group.
Reference should also be made to iron, nickel, cobalt and copper, as
the oxides of these latter metals, if in small quantity, might escape
detection by the reducing process. (See under Operation 5, pp. 13,
14, the colours imparted by these oxides to borax.)
Group 2. — Imparting no colour to the fluxes. Slowly dissolved by
borax, the glass remaining permanently clear.
Alumina.
Moistened with nitrate of cobalt and then ignited, this base assumes
on cooling a fine blue colour.
Group 3. — Imparting no colour to the fluxes. Rapidly dissolved
by borax, the glass becoming opaque on cooling or when flamed. In-
soluble in carb. soda.
Magnesia. Lime.
Moistened with nitrate of cobalt, and ignited, Magnesia becomes
pale-red in colour ; Lime, dark gray.
70 BLOWPIPE PRACTICE.
Group 4. — Entirely dissolved by fusion with carl), soda.
Baryta. Strontia. Lithia. Soda. Potash.
Baryta compounds impart a distinct green colour to the point and
border of the flame. Strontia and Lithia colour the flame deep car-
mine-red. The crimson coloration is destroyed in the case of strontia
if the substance be fused with chloride of barium. Soda colours the
flame strongly yellow. Potash communicates to it a violet tint ; but
this colour is completely masked by the presence of soda, unless the
flame be examined through a deep blue glass. See also the spectro-
scope reactions of these bodies given under their respective heads in
§5.
APPENDIX.
ORIGINAL CONTRIBUTIONS TO BLOWPIPE ANALYSIS.
BY E. J. CHAPMAN.
1.— EEACTION OF MANGANESE SALTS ON BARYTA.
When moistened with a solution of any manganese salt, and ignited
in an oxidating flame, baryta and baiyta compounds, generally,
assume on cooling a blue or greenish-blue colour. This arises from
the formation of a manganate of baryta. Strontia and other bodies
(apart from the alkalies) when treated in this manner, become brown
or dark-gray. A mixture of baryta and strontia also assumes an
indefinite grayish-brown colour. If some oxide of manganese be
fused with carbonate of soda so as to produce a greenish-blue bead or
" turquoise enamel," and some baryta or a baryta salt be melted into
this, the colour of the bead will remain unchanged ; but if strontia be
used in place of baryta, a brown or grayish-brown enamel is produced.
NOTE. — Some examples of witherite, barytine, and baryto-calcite, contain
traces of oxide of manganese. These, after strong ignition, often assume per se
a pale greenish-blue colour. 1846.
2.— DETECTION OF BARYTA IN THE PRESENCE OF STRONTIA,
This test is chiefly applicable to the detection of baryta in the
natural sulphate of strontia ; but it answers equally for the examina-
tion of chemical precipitates, &c., in which baryta and strontia may
be present together. The test-matter, in fine powder, is to be melted
in a platinum spoon with 3 or 4 volumes of chloride of calcium, and
the fused mass treated with boiling water. For this purpose, the
spoon may be dropped into a teat-tube, or placed (bottom upwards)
in a small porcelain capsule. The clear solution, decanted from any
residue that may remain, is then to be- diluted with 8 or 10 times
its volume of water, and tested with a few drops of chromate (or
bichromate) of potash. A precipitate, or turbidity, indicates the
presence of baryta. 1846.
72 BLOWPIPE PRACTICE.
3.— DETECTION OF ALKALIES IN THE PRESENCE OF MAGNESIA.
In the analysis of inorganic bodies, magnesia and the alkalies (if
present) become separated from other constituents towards the close
of the operation. In continuation of the analysis, it then becomes
desirable to ascertain, at once, whether magnesia be alone present, or
whether the saline mass, produced by the evaporation of a portion of
the solution, consist of magnesia and one or more of the alkalies, or
of the latter only. By fusing a small quantity of the test-matter with
carbonate of soda, the presence of magnesia is readily detected, as this
substance remains undissolved ; but the presence or absence of alka-
lies is not so easily determined, the coloration of the flame being
frequently of too indefinite a character to afford any certain evidence
on this point. The question may be solved, however, by the following
simple process. Some boracic acid is to be mixed with the test-matter
and with a few particles of oxide of copper, and the mixture is to be
exposed for a few seconds, on a loop of platinum wire, to the action of
an oxidating flame. In the absence of alkalies, the oxide of copper
will remain undissolved ; but if alkalies be present, an alkaline borate
is produced, forming a readily fusible glass, in \vhich the copper oxide
is at once dissolved, the glass becoming green whilst hot, and blue
when cold. If magnesia also be present, white specks remain for a
time undissolved in the centre or on the surface of the bead. Any
metallic oxide which imparts by fusion a colour to alkaline borates,
may, of course, be employed in place of oxide of copper; but the
latter has long been used in other operations, and is therefore always
carried amongst the reagents of the blowpipe-case. 1847.
4.— METHOD OF DISTINGUISHING THE RED FLAME OF LITHIUM
FROM THAT OF STRONTIUM.
It has been long known that the crimson coloration imparted to the
blowpipe-flame by strontia, is destroyed by the presence of baryta.
This reaction, confirmed by Plattner (see, more especially, the third
edition of his " Probirkunst," page 107), was observed as early as
1829 by Butsengeiger ("Annales des Mines," t v., p. 36). The
latter substance, however, as first indicated by the writer, does not
affect the crimson flame-coloration produced by lithia. Hence, to dis-
tinguish the two flames, the test-substance may be fused with 2 or 3
volumes of chloride of barium on a loop of platinum wire, the fused
APPENDIX. 73
mass being kept just within the point or edge of the blue cone. If
the original flame-coloration proceeded from strontia (or lime), an
impure brownish-yellow tinge will be imparted to the flame-border ;
but if the original red colour were caused by lithia, it will not only
remain undestroyed, but its intensity will be much increased.
This test may be applied, amongst other bodies, to the natural
silicates, lepidolite, spodumene, <fcc. It is equally available, also, in
the examination of phosphates. The mineral triphylline, for example,
when treated per se, imparts a green tint to the point of the flame,
owing to the presence of phosphoric acid ; but if this mineral be fused
(in powder) with chloride of barium, a beautiful crimson coloration in
the surrounding flame-border is at once produced. 1848.
5. -METHOD OF DISTINGUISHING THE MONOXIDE OF IKON
(FeO) FROM THE SESQUIOXIDE (Fe2O3) IN SILICATES AND
OTHER COMPOUNDS.
If iron be recognized in an oxidized body, its presence or absence
as ferrous oxide (FeO) is readily indicated by this test : assuming,
of course, that no other reducing body be present, a point easily
ascertained by the blowpipe. The test is performed as follows : A
small quantity of black oxide of copper (CuO) is dissolved in a bead
of borax on platinum wire, so as to form a glass which exhibits, 011
cooling, a decided blue colour, but which remains transparent. To
this, the test-substance in the form of powder is added, and the whole
is exposed for a few seconds, or until the test-matter begin to dissolve,
co the point of the blue flame. If the substance contain Fe2O3 only,
the glass on cooling will remain transparent, and will exhibit a bluish-
green colour. On the other hand, if the test-substance contain FeO,
this will become at once converted into Fe2O3 at. the expense of some
of the oxygen of the copper compound ; and opaque red streaks and
spots of Cu2O will appear in the glass as the latter cools. 1848.
NOTE. — Although this test is quoted by Plattner — perhaps the best criterion
of its accuracy — it is passed over, without mention, in inany works on chemical
analysis. The writer may therefore be allowed to call to mind, in proof of its
efficacy, that by its use in 1848 he pointed out the presence of FeO in the
mineral staurolite (" Chem. Gaz.," July 15, 1848; see also Erdmann's "Journal
fur pract. Chem.," XLVL, p. 119), nearly thirteen years before this fact —
now universally admitted — was discovered and announced by Rammelsberg,
"Berichte d. Kongl. preuss. Akad. d. Wiss. zu Berlin," Marz, 1861.
74 BLOWPIPE PRACTICE.
6.— DETECTION OF LEAD IN THE PRESENCE OF BISMUTH.
"When lead and bismuth are present together, the latter metal may
be readily detected by its known reaction with phosphor-salt in a
reducing flame — antimony, if present, being first eliminated ; but the
presence of lead is less easily ascertained. If the latter metal be pre-
sent in large quantity, it is true, the metallic globule will be more or
less malleable, and the flame-border will assume a clear blue colour
when made to play upon its surface, or on the sublimate of lead-oxide
as produced on charcoal ; but in other cases this reaction becomes
exceedingly indefinite. The presence of lead may be detected, how-
ever, by the following plan, based on the known reduction and
precipitation of salts of bismuth by metallic lead, a method which suc-
ceeds perfectly with brittle alloys containing from 85 to 90 per cent,
of bismuth. A small crystal or fragment of nitrate of bismuth is
placed in a porcelain capsule, and moistened with a few drops of water,
the greater part of which is afterwards poured off; and the metallic
globule of the mixed metals, as obtained by the blowpipe, having been
slightly flattened on the anvil until it begins to crack at the sides, is
then placed in the midst of the sub-salt of bismuth formed by the
action of the water. In the course of a minute or even less, according
to the amount of lead that may be present, an arborescent crystalliza-
tion of metallic bismuth will be formed around the globule. The
reaction is not affected by copper; but a precipitation of bismuth
would ensue, in the absence of lead, if either zinc or iron were present.
These metals, however, may be eliminated from the test-globule by
exposing this on charcoal for some minutes, with a mixture of carb.
soda and borax to a reducing flame. The zinc becomes volatilized,
and the iron is gradually taken up by the borax. If a single opera-
tion do not effect this, the globule must be removed from the saturated
dai-k green glass, and treated with further portions of the mixture,
until the resulting glass be no longer coloured. 1848.
7.— DETECTION OF LITHIA IN THE PRESENCE OF SODA.
This test may be applied to mixtures of these alkalies in the simple
state, or to their carbonates, sulphates, nitrates, or other compounds
capable of being decomposed by fusion with chloride of barium. The
test-substance, in powder, is to be mixed with about twice its volume
of chloride of barium, and a small portion of the mixture is to be
APPENDIX.
exposed on a loop of platinum wire to the point of a
oxidating flame. A deep yellow coloration of the flame-L^ ~™ ^.«™
duced by the volatilization of chloride of sodium, at first e&sqjkKf 1^
This gradually diminishes in intensity, and after a short time a thin
green streak, occasioned by chloride of barium, is seen to stream from
the point of the wire, as the test- matter shrinks further down into the
loop. On the fused mass being then brought somewhat deeper into
the flame, the point and edge of the latter will at once assume the rich
crimson tinge characteristic of the presence of lithium compounds ;
and the colour will endure sufficiently long to prevent the slightest
chance of misconception or uncertainty. The presence of strontium
compounds does not affect this reaction, as these compounds, when
fused with chloride of barium, cease to impart a red colour to the
flame. (See No. 4.) In order, however, to ensure success in the
application of this test, it is necessary, in some cases, to keep up a
clear and sharply-defined flame for about a couple of minutes. If the
red coloration do not appear by that time, the absence of lithia —
unless the latter substance be present in minute traces only — may be
safely concluded. 1850.
8.— ACTION OF BARYTA ON TITANIC ACID.
Fused with borax in a reducing flame, titanic acid, it is well known,
forms a dark amethystine-blue glass, which becomes light blue and
opaque when subjected to the flaming process. The amethystine
colour arises from the presence of Ti*O8 • the light blue enamelled sur-
face, from the precipitation of a certain portion of TiO2. The presence
of baryta, even in comparatively small quantity, quite destroys the
latter reaction. When exposed to an intermittent flame, the glass (on
the addition of baryta) remains dark blue, no precipitation of titanic
acid taking place. Strontia acts in the same manner, but a much
larger quantity is required to produce the reaction. 1852.
9.— DETECTION OF OXIDE OF MANGANESE WHE>I PRESENT
IN MINUTE QUANTITY IN MINERAL BODIES.
It is usually stated in works, on the blowpipe, that the smallest
traces of manganese may be readily detected by fusion with carbonate
of soda, or with a mixture of carbonate of soda and nitrate of potash :
but this statement is to some extent erroneous. In the presence of
much lime, magnesia, alumina, sesquioxide of iron, or other bodies,
76 BLOWPIPE PRACTICE.
insoluble, or of difficult solubility, in carbonate of soda, traces of oxide
of manganese may easily escape detection. By adding, however, a
small portion of borax or phosphor-salt to the carbonate of soda, these
bodies become dissolved, and the formation of a " turquoise enamel "
(manganate of soda) is readily effected. The process may be varied
by dissolving the test-substance first in borax or phosphor-salt, and
then treating the fused bead with carbonate of soda : the latter being,
of course, added in excess. By this treatment, without the addition
of nitrate of potash, the faintest traces of oxide of manganese in lime-
stone and other rocks, are at once made known. 1852.
NOTE. — This method of examining bodies for the presence of manganese,
was recommended by Dr. Leop. IL Fischer in 1861 ("Leonh. Jahrbuch "
[1861], p. 653), but the writer had forestalled him by nine years, having already
described it in 1852.
10.— THE COAL ASSAY.
In the practical examination of coals, the following operations are
essentially necessary:* (1) The estimation of the water or hygro-
* To these might be added, the determination of the heating powers or " absolute warmth '
of the coal, but this may always be estimated with sufficient exactness for practical purposes
by the amount of eoke, ash, and moisture, as compared with other coals. Properly considered,
the litharge test, resorted to for the determination of the calorific power of coals, is of very
little actual value. The respective results furnished by good wood charcoal and ordinary coke,
for example, are closely alike, if not in favour of the charcoal ; and yet experience abundantly
proves the stronger heating powers of the eoke. In practice, moreover, the actual value of a
coal does not always depend upon the " absolute warmth" of the latter, as certain coals, such
as brown coals rich in bitumen, may posses* heating powers of considerable amount (as esti-
mated by the reduction of litharge) though only of brief duration. Thus, the lignites of the
department of the Basses Alpes ia south-eastern France, and those of Cuba, yield with litharge
from 25 to 26 parts of reduced lead ; whilst many caking coals, practically of much higher heat-
ing power, yield scarcely a larger amount. When pyrites also is present in the coal — a condition
of very common occurrence — the litharge test becomes again unsatisfactory, the pyrites exerting
a reducing action on the lead compound.
As described, however, by Bruno Kerl, in quoting the writer's coal assay (" Lothrohr-Unter-
suchungen.-" Zweite Aufl. 1862, p. 146) the so-called absolute warmth or heating power of a coal
sample may be determined, if desired, in blowpipe practice, by the following modification of
Berthier's method: 20 milligrammes of the coal, in fine powder, are to be mixed intimately
with 500 milligrammes of oxy-chloride of lead (consisting of three parts of litharge + 1 part of
chloride of lead, fused together and finely pulverized). The mixture is to be placed in a blow-
pipe crucible, and covered with about an equal'araount of the lead compound, a second cover
of 3 blowpipe-spoonfuls of powdered glass + 1 ipoonful of borax being spread over this. The
crucible, covered with a clay capsule, is then to be fitted into a charcoal block in the ordinary
blowpipe furnace, over which a charcoal lid is placed, and the flame directed against its under
«ide, so as to keep it at a red heat for from 5 to 8 minutes. The weight of the reduced lead
divided by 20 gives the amount of the lead mixture reduced by one part of the coal. One part
of pure carbon reduces 34 parts of this mixture ; one part of charcoal, 30 to 33 parts ; one part
of bituminous coal, 19 to 33 ; one part of brown eoal, H to 26 ; one part of peat, 8 to 27 ; and
one part of wood, 12 to 15 parts.
APPENDIX. 77
metric moisture present in the coal ; (2) the determination of the
weight and character of the coke ; (3) the estimation and examination
of the ash or inorganic matters ; and (4) the estimation of the sul-
phur, chiefly present in the coal as FeS2.
Estimation of Moisture. — This operation is one of extreme sim-
plicity. Some slight care, however, is required to prevent other
volatile matters from being driven off during the expulsion of the
moisture. Seven or eight small particles, averaging together from
100 to 150 milligrammes, are to be detached from the assay specimen
by means of the cutting pliers, and carefully weighed. They are then
to be transferred to a porcelain capsule with thick bottom, and strongly
heated for four or five minutes on the support attached to the blow-
pipe-lamp, the unaided flame of the lamp being alone employed for
this purpose. It is advisable to place in the capsule, at the same time,
a small strip of filtering or white blotting-paper, the charring of which
will give indications of the temperature becoming too high. The coal,
whilst still warm, is then to be transferred to the little brass capsule
in which the weighings are performed, and its weight ascertained. In
transferring the coal from one vessel to the other, the larger pieces
should be removed by a pair of fine brass forceps, and the little parti-
cles or dust afterwards swept into the weighing capsule by means of
the camel's-hair pencil or small colour-brush belonging to the balance
case. The weighing capsule should also be placed in the centre of a
half sheet of glazed writing-paper, to prevent the risk of any acci-
dental loss during the transference. After the weighing, the opera-
tion must always be repeated, to ensure that no further loss of weight
occur. In place of the blowpipe-lamp, the spirit-lamp may be employed
for this operation ; but, with the former, there is less danger of the
heat becoming too high. By holding a slip of glass for an instant,
every now and then, over the capsule, it will soon be seen when the
moisture ceases to be given off. It should be remarked that some
anthracites decrepitate slightly when thus treated, in which case the
|K)rcelain capsule must be covered at first with a small watch-glass.
In good samples of coal, the moisture ought not to exceed 3 or 4 per
cent., but in coals that have been long exposed to damp it is often as
high as 6 or 7, and even reaches 1 5 or 20 per cent, in certain lignites.
Where large quantities of coal are consumed, therefore, a serious loss is
78 BLOWPIPE PRACTICE.
entailed on the purchaser unless the moisture be properly determined
and allowed for.
Estimation, <&c., of Coke. — In this operation, a small crucible of
platinum is most conveniently employed. The crucible may consist
of a coaple of rather deep spoons — the larger one without a handle,
so as to admit of being placed over the smaller spoon,
thus serving as a lid. The long handle of the cru-
cible-spoon must be bent as shewn in the annexed
figure, in order that the spoon may retain an upright
position when placed on the pan of the balance.
About 150 milligrammes of coal are detached as before, in several
small fragments, from the assay-specimen. These may be weighed
directly in the crucible, the latter being placed in the little weighing
capsule of horn or brass, with its handle-support projecting over the
side of this. The crucible, with its cover on, is then taken up by a
pair of spring forceps, and is brought gradually before the blowpipe
to a red heat. The escaping gases will take fire and burn for a few
seconds around the vessel, and a small amount of carbonaceous matter
may be deposited upon the cover. This rapidly burns off, however,
on the heat being continued. As soon as it disappears, the crucible
is to be withdrawn from the flame, and placed on the blowpipe-anvil
to cool quickly. Its weight is then ascertained, always without remov-
ing the cover. The loss, minus the weight of moisture as found by
the first process, gives the amount of volatile or gaseous matter. The
residue is the coke and its contained ash. The coke in some anthra-
cites exceeds 89 or 90 per cent. In anthracitic or dry coals it usually
varies from 70 to 80 per cent., and the fragments are sometimes slightly
agglutinated. In ordinary bituminous or caking coals, it amounts in
general to about 65 or 70 per cent., and presents a fused and mamil-
lated surface. In cannel or gas coals, the percentage of coke may be
assumed to equal 50 or 60, but it is sometimes as low as 30. The coke
fragments are often partially agglutinated, but they never present a
fused, globular aspect. Finally, in lignites or brown coals, the coke
may vary from 25 to 50 per cent. It forms sharp-edged fragments
of a dull charcoal-like appearance, without any sign of fusion.
Estimation of Ash or Inorganic Matters. — A platinum capsule is
employed for this operation. One of about half an inch in diameter,
with a short ear or handle, is sufficiently large. A somewhat smaller
APPENDIX. 79
capsule, with its handle cut off, may be fitted into this (in reversed
position) to serve as a lid. The coal must be reduced to a coarse
powder, and about 150 milligrammes weighed out for the experiment.
The platinum capsule is then to be fixed in a slightly-inclined posi-
tion above the spirit-lamp, and heated as strongly as possible. If the
wick of the spirit-lamp be raised sufficiently, and the capsule be light
and thin, the temperature will be sufficient to burn off the carbon, at
least in the majority of cases. The lid of the capsule must be placed
above the coal powder until combustion cease, and the more gaseous
products are driven off, as otherwise a portion of the powder might
very easily be lost. During the after combustion the powder must
be gently stirred, and if agglutination take place the particles must
be carefully broken up by a light steel spatula, or by a piece of stout
platinum wire flattened at one end. If the carbonaceous matter be
not burnt off by this treatment, the blowpipe may be used to accelerate
the process ; but the operator must blow cautiously, and direct the
flame only against the under side of the capsule, in order to avoid
the risk of loss. Finally, on the ash ceasing to exhibit in any of
its particles a black colour, the lid of the capsule is to be carefully
replaced, and the whole cooled and weighed.*
In good coals, the amount of ash is often under 2 per cent., and it
rarely exceeds 4 or 5 per cent. In coals of inferior quality, however,
it may vary from 8 or 10 to even 30 per cent. As regards its compo-
sition, the ash may be — (1) argillaceous, consisting essentially of a
silicate of alumina ; (2) argillo-ferruginous ; (3) calcareous ; and (4)
calcareo-ferruginous. If free from iron, it will be white or pale gray ;
but if more or less ferruginous, it will present a red, brown, or yellowish
colour. Phosphor-salt, so useful in general cases for the detection of
siliceous compounds, cannot be safely used to distinguish the nature
of the ash obtained in blowpipe assays. Owing to their fine state of
division and to the small quantity at command, argillaceous ashes dis-
solve in this reagent with as much facility as those of a calcareous
nature, and without producing a characteristic silica skeleton, or
causing the opalization of the glass. With calcareous ashes also, the
* If the ash be very ferruginous— in which case it will present a red or tawny colour— the
results, as thus obtained, will require correction, the original iron pyrites of the coal being
weighed as sesquioxide of iron. In ordinary assays, however— as distinguished from analyses—
this may be fairly neglected. When also the ash happens to be calcareous and to occur in large
quantity, it should be moistened with a drop or two of a solution of carbonate of ammonia, and
gently heated, previous to being weighed.
80 BLOWPIPE PRACTICE.
amount obtained is rarely sufficient to saturate even an exceedingly-
minute bead of phosphor-salt or borax, and hence no opacity is pro-
duced by the flaming process. The one kind of ash may be distin-
guished, nevertheless, from the other, by moistening it, and placing
the moistened mass on reddened litmus paper. Calcareous ashes
always contain a certain amount of caustic lime, and thus restore the
blue colour of the paper. The calcareous ashes, also, though princi-
pally composed of carbonate of lime, sometimes contain small portions
of phosphate and sulphate of lime. The presence of the latter may
be readily detected by the well-known production of an alkaline sul-
phide by fusion with carbonate of soda in a reducing flame — the fused
mass exhibiting a reddish colour, and imparting when moistened a dark
stain to a plate of silver or piece of lead test-paper. The latter may
be replaced by a glazed visiting-card. In examining earthy sulphates
by this method, a little borax ought always to be added to the car-
bonate of soda, in order to promote the solution of the test-matter.
If oxide of manganese be present in the ash, the well-known man-
ganate of soda, or " turquoise enamel," will also be obtained by this
treatment.
Estimation of Sulphur. — The following plan is perhaps the most
simple that can be employed for the determination of sulphur in coal
samples. It is merely an adaptation to blowpipe practice of the pro-
cess very generally employed for that purpose ;
As large an amount of coal as practicable, several pounds at least,
taken from different parts of the same heap or bed, must be broken
into powder and well stirred together. About 150 milligrammes are
to be weighed out for the assay. This amount is to be intimately
mixed with about 450 milligrammes of nitrate of potash and an equal
quantity of carbonate of potash, and the mixture, with a good cover-
ing of salt, is to be fused in a small platinum crucible of about a
quarter of an ounce capacity. The crucible may be fixed in an
ordinary blowpipe-furnace, in the centre of an already used charcoal-
block, as the cavity of the latter will require to be larger than usual ;
or it may be ignited by the flame of a Bunsen burner, without the
aid of the blowpipe. The heat at first must be very moderate, as
the mixture swells up greatly ; but after a couple of minutes, or
thereabouts, a tolerably strong blast may be kept up for from two to
three minutes in addition, when the operation will be finished. The
APPENDIX. 81
alkalino sulphate, thus produced, is dissolved out by boiling water,
and the filtered solution, acidified by a few drops of hydrochloric acid,
is then treated with chloride of barium. The weight of the pre-
cipitate divided by 7.28 gives the amount of sulphur. An ordinary
blowpipe-crucible of clay may be employed for this operation ; but it
is always strongly attacked by the mixture during fusion, and is
otherwise less convenient for the purpose than one of platinum.
When the iron pyrites in the coal is not in a state of semi-decom-
position, its amount, and consequently the amount of sulphur, may
be arrived at far more nearly than might at first thought be supposed,
by the simple process of washing in the agate mortar. Each single
part of pyrites corresponds to 0.533 of sulphur. Some large pieces
of the assay-coal should be selected, and broken up into powder ; and
on this, several trials must be made. About 500 milligrammes may
be taken for each trial, and washed in three or four portions. In
the hands of one accustomed to the use of the mortar in reducing
experiments, the results, owing to the lightness of the coal particles,
and the consequent ease with which they are floated off, come out
surprisingly 'near to the truth. In travelling, we may dispense with
the washing bottle, by employing, in its place, a piece of straight
tubing drawn out abruptly to a point. This is to be tilled by suction,
and the water expelled with the necessary force by blowing down the
tube. A tube 6 inches long and the fourth of an inch in diameter
will hold more than a sufficient quantity of water to be used between
the separate grindings. The mortar should be but slightly inclined,
and the stream of water must not be too strong : otherwise, especially
if the coal be ground up very fine, portions of the pyrites may be
lost. The proper manipulation, however, is easily acquired by a
little practice. 1858.
11.— PHOSPHORUS IN IRON WIRE.
Many years ago, it was stated by GRIFFIN that thin iron wire
exhibits, in burning, a green light. This statement is repeated by
Prof. GALLOWAY in various editions of his useful little work on
chemical analysis : iron wire being placed in one of the tables, given
in that manual, among the substances which impart a green colora-
tion to the blowpipe-name. On the other hand, neither BERZELIUS,
PLATTNER, RICHTER, VON KOBELL, DR. HARALD LENZ (Die
7
82 BLOWPIPE PRACTICE.
Lothrohrschule, 1848J, SCHEERER, BRUNO KEEL, nor any other of
the numerous workers with the blowpipe on the continent of Europe
have ever alluded to the reaction. LENZ gives a minute description
of the action of the blowpipe-flame on iron wire, and points out that
the fusion is always accompanied by oxidation ; but he makes no
allusion to any coloration of the flame. Struck by this apparent
omission, I have examined a number of samples of iron wire by the
blowpipe. All the light-coloured and comparatively hard wires
exhibited the reaction very distinctly. A bright green flame streamed
from the point of the wire during the oxidation and fusion of the
latter, and a rapid scintillation or emission of sparks accompanied
the phenomenon. On the other hand, the soft and dark wires fused
much less readily, and did not occasion the slightest coloration of the
flame. The green flame-coloration, occasioned by the harder wires,
arises, I find, from the presence of a minute amount of phosphorus,
this being converted into phosphoric acid during the combustion of
the wire. As iron-wire is often employed in blowpipe practice as a
reagent for phosphoric acid in phosphates, and as it is also occasion-
ally used in preparing a solution of iron oxide (Fe2O3) for the estima-
tion of phosphoric acid in bodies generally, the publication of the
present note may not be altogether superfluous. 1864.
12.— DETECTION OF MINUTE TRACES OF COPPER IN IRON
PYRITES AND OTHER BODIES.
Although an exceedingly small percentage of copper may be detected
in blowpipe experiments by the reducing process, as well as by the
azure-blue coloration of the flame when the test-matter is moistened
with hydrochloric acid, these methods fail in certain extreme cases to
give satisfactory results. It often happens that veins of iron pyrites
lead at greater depths to copper pyrites. In this case, according to
the experience of .the writer, the iron pyrites will almost invariably
hold minute traces of copper. Hence the desirability, in exploring
expeditions more especially, of some ready test, by which, without
the necessity of employing acids or other bulky and difficultly portable
reagents, these traces of copper may be detected. The following-
simple method will be found to answer the purpose: The test-sub-
stance, in powder, must first be roasted on charcoal, or, better, on a
APPENDIX. 83
fragment of porcelain,* in order to drive off the sulphur. A small
portion of the roasted ore is then to be fused on platinum wire with
phosphor-salt ; and some bisulphate of potash is to be added to the
glass (without this being removed from the wire) in two or three suc-
cessive portions, or until the glass becomes more or less saturated.
This effected, the bead is to be shaken oft' the platinum loop into a
small capsule, and treated with boiling water, by which either the
whole or the greater part will be dissolved ; and the solution is finally
to be tested with a small fragment of ferrocyaiiid of potassium
(" yellow prussiate.") If copper be present in more than traces, this
reagent, it is well known, will produce a deep red precipitate. If the
copper be present in smaller quantity, that is, in exceedingly minute
traces, the precipitate will be brown or brownish-black ; and if copper
be entirely absent, the precipitate will be blue or green — assuming,
of course, that iron pyrites or some other ferruginous substance is
operated upon. In. this experiment, the preliminary fusion with
phosphor-salt greatly facilitates the after solution of the substance in
bisulphate of potash. In some instances, indeed, no solution takes place
if this preliminary treatment with phosphor-salt be omitted. 1865.
13.— DETECTION OF ANTIMONY IN TUBE-SUBLIMATES.
In the examination of mineral bodies for antimony, the test-sub-
stance is often roasted in an open tuba for the production of a white
sublimate. The presence of antimony in this sublimate may be
detected by the following process — a method more especially availably
when the operator has only a portable blowpipe-case at his command..
The portion of the tube to which the chief portion of the sublimate is
attached is to be cut off by a triangular file, and dropped into a test-
tube containing some tartaric acid dissolved in water. This being
warmed or gently boiled, a part at least of the sublimate will be dis-
solved. Some bisulphate of potash — either alone, or mixed with some
carb. soda and a little borax, the latter to prevent absorption — is then,
* In the roasting of metallic sulphides, &c., the writer has employed, for some years, small
fragments of Berlin or Meissen porcelain, such as result from, the breakage of crucibles and
other vessels of that material. The test-substance is crushed to po\yd.er, moist,ened slightly,
and spread over the surface of the porcelain ; and when the operation is finished,- tke, powder is
eisily scraped off by the point of a knife-blade or small &teel-spat,ula. In roasting operations,
rarely more than a dull red heat is required ; but these porcelain fragments may be rendered
white-hot, if such be necessary, without risk of fracture. They are held, most conveniently, by
a. pair of spring-forceps.— "Canadian Journal," September, I860.
84 BLOWPIPE PRACTICE.
to be fused on charcoal in a reducing flame ; and the alkaline sulphide,
thus produced, is bo be removed by the point of a knife-blade, and
placed in a small porcelain capsule. The hepatic mass is most easily
separated from the charcoal by removing it before it has time to soli-
dify. Some of the tartaric acid solution is then to be dropped upon
it, when the well-known orange-coloured precipitate of Sb2S3 will at
once result.
In performing this test, it is as well to employ a somewhat large
fragment of the test-substance, so as to obtain a thick deposit in the
tube. It is advisable also to hold the tube in not too inclined a posi-
tion in order to let but a moderate current of air pass through it ;
and care must be taken not to expose the sublimate to the action of
the flame — otherwise it might be converted almost wholly into a com-
pound of Sb2O3 and Sb'2O5, the greater part of which would remain
undissolved in the tartaric acid solution. A sublimate of arbenious
acid, treated in this manner, would, of course, yield a yellow precipi-
tate, easily distinguished by its colour, however, from the deep orange
antimonial sulphide. The crystalline character, etc., of the sublimate,
would also effectually prevent any chance of misconception.
14.— ON THE REACTIONS OF METALLIC THALLIUM BEFORE
THE BLOWPIPE.
The following reactions are given from direct experiments by the
writer : *
In the closed tube, thallium melts easily, and a brownish-red
vitreous slag, which becomes pale yellow on cooling, forms around
the fused globule.
In the open tube, fusion also takes place on the first application of
the flame, whilst the glass becomes strongly attacked by the formation
of a vitreous slag, as in the closed tube. Only a small amount of
*The reactions given by Crookes are as follows: "The metal melts instantly on charcoal,
and evolves copious brown fumes. If the bead is heated to redness, it glows for some time after
the source of heat is removed, continually evolving vapours which appear to be a mixture of
metal and oxide. A reddish amorphous sublimate of proto-peroxide surrounds the fused
globule. When thallium is heated in an open glass tube, it melts and becomes rapidly con-
verted into the more fusible protoxide, which strongly attacks the glass. This oxide is of a
dark red colour when hot, solidifying to a brown crystalline mass. The fused oxide attacks
glass and porcelain, removing the silica. Anhydrous peroxide of thallium is a brown powder,
fusing with difficulty and evolving oxygen at a red heat, becoming reduced to the protoxide.
The phosphate and sulphate will stand a red Ueat without change."
APPENDIX. 85
sublimate is produced. This is of a grayish- white colour, but under
the magnifying-glass it shews in places a faint iridescence.
On charcoal, per se, thallium melts very easily, and volatilizes in
dense fumes of a white colour, streaked with brown, whilst it imparts
at the same time a vivid emerald-green coloration to the point and
edge of the flame. If the heat be discontinued, the fused globule con-
tinues to give off copious fumes, but this action ceases at once if the
globule be removed from the charcoal. A deposit, partly white and
partly dark brown, of oxide and teroxide is formed on the support ;
but, compared with the copious fumes evolved from the metal, this
deposit is by no means abundant, as it volatilizes at once where it
comes in contact with the glowing charcoal. If touched by either
flame, it is dissipated immediately, in imparting a brilliant green
colour to the flame-border. The brown deposit is not readily seen on
charcoal ; but if the metal be fused on a cupel, or on a piece of thin
porcelain or other non-reducing body, the evolved fumes are almost
wholly of a brownish colour, and the deposit is in great part brownish-
black. It would appear, therefore, to consist of T1O3, rather than of
a mixture of metal and oxide. On the cupel, thallium is readily
oxidized and absorbed. It might be employed, consequently, as
suggested by Crookes, in place of lead in cupellation ; but, to effect
the absorption of copper or nickel, a comparatively large quantity is
required. When fused on porcelain, the surface of the support is
strongly attacked by the formation of a silicate, which is deep red
whilst hot, and pale yellow on cooling.
The teroxide, as stated by Crookes, evolves oxygen when heated,
and becomes converted into T1O. The latter compound is at once
reduced on charcoal, and the reduced metal is rapidly volatilized with
brilliant green coloration of the flame. The chloride produces the
same reaction, by which the green flame of thallium may easily be
distinguished from the green copper-flaine ; the latter, in the case of
cupreous chlorides, becoming changed to azure-blue. With borax
and phosphor-salt, thallium oxides form colourless glasses, which
become gray and opaque when exposed for a short time to a reducing
flame. With carb. soda, they dissolve to some extent, but on char-
coal a malleable metallic globule is obtained. The presence of soda,
unless in great excess, does not destroy the green coloration of the
flame.
86 BLOWPIPE PRACTICE.
Thallium alloys more or less readily with most other metals before
the blowpipe. With platinum, gold, bismuth, and antimony, respec-
tively, it forms a dark-gray brittle globule. With silver, copper, or
lead, the button is malleable. With tin, thallium unites readily, but
the fused mass immediately begins to oxidize, throwing out excres-
cences of a dark colour, and continuing in a state of ignition until
the oxidation is complete. In this, as in other reactions, therefore,
the metal much resembles lead. 1876.
15.— ON THE OPALESCENCE PRODUCED BY SILICATES IN
PHOSPHOR-SALT.
It is well known that most silicates when fused with phosphor-salt
are only partially attacked ; the bases, as a rule, gradually dissolving
in the flux, whilst the silica remains in the form of a flocculent mass
technically known as a " silica skeleton." Very commonly, almost
invariably indeed, if the blast be long continued, the bead becomes
more or less milky or opalescent on cooling. This latter reaction was
apparently regarded by Plattner as essentially due to the presence of
alkaline or earthy bases, such as exhibit the reaction per se. He states,
" Probirkunst," Dritte A ullage, p. 468 : " Da man nun von mehreren
Silikaten ein Glas bekommt, welches, so lange es heiss ist, zwar klar
erscheint, aber unter der Abkiihlung mehr oder weniger opalisirt, so
muss man sich von der ausgeschiedenen Kieselsaure iiberzeugen, so
lange das Glas noch heiss ist, und dabei die Loupe z'u Hiilfe nehmen.
Die so eben erwahnte Erscheinting tritt gewohnlich bei solchen Sili-
katen ein, deren Basen, Kalkerde, Talkerde, Beryllerde oder Yttererde
sind, die fur sich mit Phosphorsalz, bei gewisser Sattigung des Glases,
unter der Abkiihlung oder durch Flattern milchweiss oder opalartig
werden." Dr. Theodor Richter, the editor of the 4th edition of
Plattner's work, leaves out the " gewohnlich " of the above quotation,
a.nd so makes the implication still stronger. In this vierte Auflage,
the statement runs : " Bei solchen Silikaten deren Basen fur sich mit
Phosphorsalz, bei gewisser Sattigung des Glases, unter der Abkiih-
lung oder durch Flattern milchweiss oder opalartig werden (Kalkerde}
Talkerde, Beryllerde, oder Yttererde) wjrd die Perle unter der
Abkiihlung mehr oder weniger triibe." It is true enough that sili-
cates in which these bases are present exhibit the reaction } but as
other silicates, practically all, indeed, exhibit the reaction also, the
inference implied in the above statement is not admissible. The
APPENDIX. 87
opalescence of tlie glass arises entirely from precipitated silica. If the
blast be sufficiently kept up, a certain amount of silica is almost
always dissolved, but this becomes precipitated as the glass cools. A
simple experiment will shew that this is the true cause of the opales-
cence. If some pure silica (or a silicate of any kind), in a powdered
condition, be dissolved before the blowpipe-flame in bora.x until the
glass be nearly saturated, and some phosphor-salt be then added, and
the blowing be continued for an instant, a precipitation of silica will
immediately take place, the bead becoming milky — or, in the case of
many silicates, opaque-white — on cooling. This test may be resorted
to for the detection of silica in the case of silicates which dissolve
with difficulty in phosphor-salt alone, or which do not give a well-
pronounced "skeleton" with that reagent.* 1876.
16.— ON THE REACTIONS OF CHROMIUM AND MANGANESE
WITH CARBONATE OF SODA.
When a mineral substance is suspected to contain manganese, it is
commonly tested by fusion with carbonate of soda. But chromium
compounds form with that reagent a green or greenish-yellow enamel,
much resembling that formed by some compounds of manganese.
The chromate-of-soda enamel, however, is yellowish-green after
exposure to an oxidating flame, and the green colour never exhibits
any tinge of blue.
The manganate-of-soda enamel, on the other hand is generally
greenish-blue when quite cold.
To avoid, however, any risk of error in the determination, the
bead may be saturated with vitrified boracic acid, until all the car-
bonic acid is expelled, and a clear glass is obtained. The chrome
glass will retain its green colour, whilst the manganese glass will
become amethystine or violet. In place of boracic acid, silica may
* By whom was the formation of a " silica skeleton" first made known? There is no reference
to it in the early treatise of Von Engestrom attached to his translation of Cronstedt's " Miner-
alogie," 1st edition, 1770 ; 2nd edition, by John Hyacinth de Magellan, 1788), although phosphor-
salt is mentioned as a reagent under the term of sr'l fusibile microcosmicnm, and was indeed used
by Cronstedt before 1758, the year in which his " Mineralogie " was anonymously published.
Bergmann, who followed as a blowpipe worker, states that "siliceous earth "is very slowly-
attacked by mieroeosmie salt, but lie does not seem to have remarked the skeleton formation
in the case of any silicate. The reaction appears to have been first definitely pointed out by
Berzelius in his staudard work on the blowpipe, published in 1820. It was therefore most
probably discovered by him, or perhaps— as he lays no claim to its discovery, whilst claiming
to be the originator of other tests— it may have been eomnmuieated to him by Gahn?
88 BLOWPIPE PRACTICE.
be used if more convenient. In tliis case the reaction is assisted by
the addition of a very small amount of borax. 1871-76.
17.— ON THE DETECTION OF CADMIUM IN THE PRESENCE OF
ZINC IN BLOWPIPE EXPERIMENTS.
When cadmiferous zinc ores, or furnace-products derived from
these, are treated in powder with carb. soda on charcoal, the charac-
teristic red-brown deposit of cadmium oxide is generally formed at
the commencement of the experiment. If the blowing be continued
too long, however, this deposit may be altogether obscured by a thick
coating of zinc oxide. When, therefore, the presence of cadmium is
suspected in the assay-substance, it is advisable to employ the fol-
lowing process for its detection. The substance, if in the metallic
state, must first be gently roasted on a support of porcelain or other
non-reducing body. Some of the resulting powder is then fused with
borax or phosphor-salt on a loop of platinum wire, and bisulphate of
potash in several successive portions is added to the fused bead. The
latter is then shaken off the wire into a small porcelain capsule, and
treated with boiling water. A bead of alkaline sulphide is next pre-
pared by fusing some bisulphate of potash on charcoal in a reducing
flame, and removing the fused mass before it hardens. A portion of
the solution in the capsule being tested with this, a yellow precipi-
tate will be produced if cadmium be present. The precipitate can
be collected by decantation or filtration, and tested with some carb.
soda on charcoal. This latter operation is necessary, because if either
antimony or arsenic were present, an orange or yellow precipitate
would also be produced by the alkaline sulphide. By treatment
with carb. soda on charcoal, however, the true nature of the precipi-
tate would be at once made known. 1876.
18.— ON THE SOLUBILITY OF BISMUTH OXIDE IN CARBONATE
OF SODA BEFORE THE BLOWPIPE.
Neither in the treatise of Berzelius, nor in the more modern and
advanced work of Plattner, is any reference made to the behaviour
of oxide of bismuth with carb. soda in an oxidating flame. In
Plattner's " Tabellarishe Uebersicht des Verhaltens der Alkalien,
Erden, und Metalloxyde fur sich und mit Reagentien im Lbthrohr-
feuer," whilst oxide of lead is stated} correctly, to be soluble in carb.
APPENDIX. 89
soda in an oxidating flame, the reference to oxide of bismuth is,
simply, that with carb. soda on charcoal it becomes immediately
reduced to metailic bismuth; and none of his translators seem to
have thought it necessary to supply the omission. In Hartmann's
tabular " Untersuchimgen mit dem Lothrohr," in the handy little
work of Bruno Kerb (" Leitfaden bei qualitativen und quantitativen
Lbthrohr-Untersuchuiigeii "), in the " Lothrohr-Tabellen " of Hirsch-
wald, and all other blowpipe books that I have met with, the same
singular omission occurs. This seems to bear out very forcibly the
somewhat cynical adage that " books are made from books." To
supply the omission, it may be observed that bismuth oxide dissolves
in carb. soda very readily in an oxidating flame, if the supporting
agent be platinum wire or other non-reducing body. The glass is
clear yellow whilst hot, but on cooling it assumes an orange or yel-
lowish-brown colour, and becomes pale yellow and opaque when cold.
As regards their solubility by fusion in carb. soda, metallic oxides
fall into three gtoups: (1) Easily soluble, e.g., PbO, Bi'O3, BaO, &c.;
(2) Slightly or partially soluble, e.g., Mn'O8, CoO, &c.; and (3),
Insoluble, e.g., Fe203, Ce'O3, NiO, CaO, MgO, &c. 1876.
19.— ON THE DETECTION OF CARBONATES IN BLOWPIPE
PRACTICE.
A mineral substance of non-metallic aspect, in nine cases out of
ten, will be either a silicate, sulphate, phosphate, borate, carbonate,
fluoride, or chloride : more especially if the streak be uncoloured or
merely exhibit some shade of green or blue, or if the substance evolve
no fumes when heated on charcoal.
Simple fusion with phosphor-salt on a loop of platinum wire
serves at once to distinguish a silicate from any of the other bodies
enumerated above, as, whilst the silicate is but slowly attacked,
these other bodies are readily and rapidly dissolved. Among the
latter, again, the carbonates are distinguished very readily by the
marked effervescence which they produce in the bead by the evolution
of carbonic acid during fusion — the phosphates, sulphates, &c., dis-
solving quietly. The reaction is quite as distinctive as that produced
by the application of an ordinary acid ; but, of course, it may arise
in both cases not only from a carbonate proper, but from the presence
of intermixed calcite or other carbonate in the su bstance under exami
90 BLOWPIPE PRACTICE.
nation ; and it is also occasioned by bodies which evolve oxygen on
ignition; but these latter, manganese oxides excepted, are of rare
occurrence among minerals proper. By this reaction, upwards of
twenty years ago, the writer detected the presence of carbonate of
lime in certain specimens of Wernerite (the " Wilsonite " variety,
portions of which had previously been analyzed without the impurity
having been discovered. It need scarcely be stated that the test-
substance must be added to the phosphor-salt, on the platinum loop,
only after the quiet fusion of the flux into a transparent glass. The
reaction is, of course, manifested equally well with borax. 1871-76.
20.— ON THE DETECTION OF BROMINE IN BLOWPIPE
EXPERIMENTS.
"When fused with phosphor-salt and copper oxide, the bromides, it
is well known, impart .an azure-blue coloration to the flame, much
like that produced by chlorides under similar treatment, although
streaked more or less with green, especially at the commencement of
the operation. To distinguish these bodies more closely, Berzelius
recommended the fusion of the test-substance with 6 or 7 volumes of
bisulphate of potash in a closed tube. Bromides by this treatment
become decomposed as a rule, and give off strongly-smelling brownish
or yellowish-red vapours of bromine. But this process does not
always give satisfactory results, as in some instances the bromide is
very slightly attacked. In this case, the following method, based on
a peculiar reaction of bromide of silver, first pointed out by Plattner,
may be resorted to : If insoluble, the bromide is fused with 2 or 3
volumes of carb. soda. A soluble bromide of sodium is thus formed,
with separation of the base. To the filtered or decanted solution
of the fused mass, a small fragment of nitrate of silver is added, in
order to precipitate bromide of silver. This, collected by decanta-
tion, is fused with a small quantity of bisulphate of potash in a little
flask or test-tube. The bromide of silver will quickly separate from
the flux in the form of a blood-red globule, which becomes pale-
yellow when cold. The little globule, washed out of the tube by
dissolving the fused bisulphate in some warm water, is carefully dried
bv being rubbed in a piece of blotting or filtering paper, and is then
placed in the sunlight. After a short time it will turn green. Chlo-
ride of silver, as obtained in a similar manner, melts into an orange-
red globule, which changes to clear-yellow on cooling, and finally
APPENDIX. 91
becomes white, or nearly so. Placed in sunlight, it rapidly assumes
a dark-gray colour. Iodide of silver, under similar treatment, forms
whilst hot an almost black globule, which becomes amethyst-red
during cooling, and dingy-yellow when cold. In the sunlight it
retains the latter colour. A mixture of chloride and iodide of silver
assumes a greenish tint somewhat resembling the colour acquired by
the bromide globule. This, however, can scarcely give rise to any
error, as the presence of iodine is revealed — even if no violet-coloured
fumes be emitted — -by the dark amethystine colour of the bead whilst
hot. 1876.
21.— BLOWPIPE REACTIONS OF METALLIC ALLOYS.
In examining these reactions, about equal portions of the metals
(forming the alloy) may be placed together, on charcoal, and subjected
to the action of a reducing flame.
1. Platinum and Tin unite with violent deflagration and emission
of light, forming a hard, brittle, and infusible globule.
2. Platinum, Zinc and Tin unite with violent action, the zinc
throwing off long flakes of oxide.
3. Platinum and Zinc, per se, do not combine, the zinc burning
into oxide.
4. Platinum and Lead unite quietly, forming a brittle globule.
5. Platinum and Thallium unite quietly ; the resulting globule is
dark externally, gray internally, and quite brittle.
6. Platinum and Bismuth unite quietly, or with merely slight
spitting, into a dark, brittle globule.
7. Platinum and Copper combine quietly, though not very readily,
into a hard, light-coloured, malleable globule.
8. Platinum and Silver unite quietly, but not very readily, unless
the silver be greatly in excess, into a white malleable globule.
9. Platinum and Gold unite quietly, forming (if the gold be some-
what in exqess) a yellow malleable globule.
10. Gold and Tin unite quietly into a very brittle globule.
1 1. Gold and Zinc do not combine per se; the zinc burns into oxide.
12. Gold and Lead combine quietly, forming a gray brittle bead.
13. Gold and Thallium unite quietly, but separate again to some
extent during cooling. The globule may thus frequently be flattened
out, but not without cracking at the sides. If the metals remain
united., the button is dark blackish -gray, and quite brittle.
92 BLOWPIPE PRACTICE.
14. Gold and Bismuth unite quietly and readily, forming a very
brittle globule.
15. Gold and Copper, and 16, Gold and Silver, unite, and form a
malleable globule.
17. Silver and Tin unite quietly into a malleable globule.
18. Silver and Lead unite readily into a malleable globule.
19. Silver and Thallium combine readily : the globule is malleable.
20. Silver and Bismuth unite readily and quietly : the globule is
brittle, but admits of being slightly flattened out.
21. Silver and Copper, and 22, Silver and Gold, form malleable
globules. The gold alloy, even with gold largely in excess, is quite
white. If it be flattened out and heated in a platinum spoon with
some bisulphate of potash, it will become yellow from the silver
on the surface being dissolved. On re-melting the flattened disc, a
silver-white globule is again obtained.
23. Copper and Tin unite into a gray and partially malleable bead,
the surface of which, in the 0 F, becomes more or less thickly encrusted
with cauliflower-like excrescences of oxide.
24. Copper and Zinc do not unite, per se, into a globule, the zinc
burning into oxide. Under carb. soda, or carb. soda and borax, brass
is readily formed.
25. Copper and Lead form a dark gray globule, which is sufficiently
malleable to admit of being extended on the anvil.
26. Copper and Thallium melt into a dark gray malleable globule.
27. Lead and Tin unite readily, but the globule commences imme-
diately to oxidize, throwing out excrescences of white and yellow
oxide. On removal from the flame it still continues in ignition, and
pushes out further excrescences. The unoxidized internal portion (if
any remain) is malleable.
28. Lead and Bismuth unite readily : the molten globule acquires
a thin dark coating of oxide on the surface only, and admits of being
flattened out, more or less, upon the anvil.
29. Lead and Thallium form a malleable globule.
30. Bismuth and Tin unite readily, but the fused mass immediately
throws out excrescences, and becomes covered with a dense crust of
oxides. The reaction, however, is not so striking as with lead and tin.
31. Thallium and Tin exhibit the same reaction as lead and tin.
but the cauliflower-like excrescences are brownish-black. 1876,
THE
fumVERSITY
PAET II.
ORIGINAL TABLES
(BASED ESSENTIALLY ON BLOWPIPE CHARACTERS)
DETERMINATION OF ALL KNOWN MINERALS.
PAET II.
INTRODUCTION
In these Tables for the Determination of Minerals, an attempt
has been made to place in the same Table, or under its secondary
sub-divisions, those minerals only which are related to each other :
related, that is, not by a single determinative character, but by their
composition and characters generally. It is not, of course, possible
to effect this with complete success in all cases; but the present
Tables, it is thought, will be found for the greater part to be at least
free from the startlingly incongruous, and hence objectionable, group-
ings seen in Determinative Mineral Tables hitherto published. At
the same time, as regards ready application and efficacy in a purely
determinative point of view, the present Tables will compare favour-
ably, it is hoped, with other efforts in this direction. In using the
Tables, the student is assumed to be familiar with the more common
blowpipe-operations and reactions, as given in Part I of this Essay.
It has not been thought necessary, therefore, in prefixing to subordi-
nate sections the headings " Cu reaction," " Pb reaction," "Na re-
action," &c., to give these reactions in full.
The present work is not, of course, intended to serve as a substi-
tute for an ordinary text-book, but simply as an adjunct to the latter.
To add, however, to its usefulness, the leading characters of each
species, including Composition, System of Crystallization (with an
occasional angle), Hardness, Specific Gravity, Colour, &c., are briefly
given. The composition is stated in percentage values in most cases ;
96 BLOWPIPE PRACTICE.
but in others merely the components, as separated by analysis— e. g.,
CaO, FeO, A1203, Fe2O3, CO2, SiO3, &c.— are stated. The student
will thus be able, after determining a mineral by the Tables, to
verify its composition as a confirmatory test.
Tne names of the Crystal Systems are printed chiefly in abbrevi-
ated form, as follows : — Reg. ( — Regular, Tesseral, Isometric, Mono-
metric, &c.); Tet. ( = Tetragonal, Quadratic, Dimetric, &c.) ; Hex.
( = Hexagonal), or Hemi-Hex. ( — Khombohedral and other Hemi-
Hexagonal forms) ; JKh. ( = Rhombic, Ortho-Rhombic, Trimetric, &c.) ;
Clino-Rh. (= Clino-Rhombic, Monoclinic, Oblique Rhombic, &c.) ;
Anorth. ( =Anorthic, Triclinic, Clino-rhomboidal, &c.) In Rhombic
and Clino-Rhombic crystals, the prism angle ( = oo P : oo P. Nau-
mann) is sometimes given under the symbol of V : V, and other
interfacial angles are occasionally stated.*
Hardness ( = H) refers, of course, to the universally adopted Scale
of Mohs. This scale is given below, together with a roughly corres-
ponding scale (published by the author in 1843) to serve as a substi-
* In the system of crystallographic notation long followed by the author- one that possesses
the advantage of allowing the symbols to be readily translated into words — all forms (apart
from those of the Regular System, and certain special forms of the Hexagonal System, in the
case of which it is more convenient to employ arbitrary symbols) are referred to one of three
sets, namely : Vertical forms (parallel with the vertical axis) ; the Basal form (parallel with the
basal or middle axes) ; and Polar or Pyramidal forms (inclined towards the vertical axis or
principal poles of the crystal). Vertical forms, generally, are denoted by the common symbol
V ; the basal form, by B ; and polar or pyramidal forms, by P. When a form lies parallel to
any axis, the sign of the axis (where this is necessary to indicate the position of the form) is
placed above the symbol. Thus V denotes a vertical form consisting of planes parallel with the
vertical axis only, as the upright planes of a rhombic prism, for example ; whilst V (in verbal
language, a " Front Vertical," = a Macro-Vertical or Ortho- Vertical, according to the System)
denotes a form parallel with the right-and-left transverse axis (= the macrodiagonal or ortho-
diagonal, as the case may be); and V or V denotes a "Side-Vertical," " Brachy- Vertical " or
" Clino-Vertical," parallel with vertical and brachy-axis, or vertical and clino-axis, according
to the System. B, the symbol of the basal form, needs no axial signs, as it cannot vary. The
polar forms comprise : Polars or Pyramids proper, Front Polars, and Side Polars (or macro-
polars, brachy-polars, &c.), and are indicated, respectively, by the symbols P, "P, and P or P
(with secondary signs where necessary, as in the Clino-Rhombic and Anorthic Systems). Values
placed before a symbol, as 2P, $P, &c., refer to the vertical axis ; those placed after a symbol,
as V2 or V2, refer to one of the middle axes, either understood conventionally, or indicated by
its sign above the figure. It is of course evident that 110 other forms than Vertical, Basal, or
Polar forms can possibly be present in any crystal Hence, by the employment of the sym-
bols V, B, and P, with modifications as described above, the position of a given form becomes
taken up by the eye at a glance, and without risk of misconception.
INTRODUCTION TO MINERAL TABLES.
97
tube where the minerals o: which the scale of Mohs consists may
not be at hand.
SCALE OF MOHS.
CHAPMAN'S CONVENIENT SCALK, TO CORRESPOND
WITH THAT OF MoHS.
1 . Talc.
I
. . Yields to the finger-nail.
2 . Rock Salt.
2
. . Doss not yield to the nail, but is scratched
3 . Calcite.
by a copper coin.
4 . Fluor Spar.
3
. . Scratches a copper coin (i. e., a copper
5 . Apatite.
coin proper, not a modern bronze coin),
(> . Orthoclase.
but is also scratched by one.
7 . Rock Crystal (Quartz).
4
. . Not scratched by a copper coin, but
8 . Topaz.
easily scratched by a penknife. Does
9 . C >ruirlum.
not scratch ordinary window-glass.
10 . Diamond.
5
. . Scratches glass very feebly, leaving its
powder on it.
6
. . Scratches glass strongly. Not scratched
by a penknife, but yields to a hard file.
Readily scratched by a piece of quartz.
t
7
. . Scarcely touched by a file.
8
- 9 - 10 . . Harder than quartz.
Convenient objects for the comparison of
minerals possessing a higher degree of hard-
ness than No. 7, cannot readily be found ; but
these minerals are few in number, and, as a
rule, they are easily distinguished by other
characters.
The sign G indicates specific gravity. This character is ascertained
very expeditiously by the spring balance contrived by Professor Jolly
of Munich ; but where an instrument of this kind is not at hand, a
small pair of ordinary scales may be conveniently used. The centre
of one pan is perforated for the passage of a horse-hair with running
noose (to hold the mineral), or is provided on its under-side with a
small hook to which the hair is attached, and the strings of this pan
should be somewhat shortened. The mineral — a small crystal or
fragment of about a gramme or couple of grammes in weight — is
weighed first in the ordinary way, and the weight is then taken
whilst the mineral is suspended in distilled water. If $ equal, the
the weight in air, and w the weight in water, G = . Bodies
a - w
which are soluble in water may be weighed in alcohol or other suit-
able liquid of known sp. gr. Galling this latter, $?',. and the weight
of the mineral in the liquid. W' the true sp. «i?. becomes , G',
a- w
98 BLOWPIPE PRACTICE.
In other words, the sp. gr. of the substance as found by the liquid,
must be multiplied by the sp. gr. of the latter.
In testing the solubility, &c., of minerals in acids, a small frag-
ment of the substance should be reduced to powder; and some of the
latter (inserted into a test-tube by a narrow strip of glazed paper
folded gutter-wise) may be covered to the depth of about half-an-inch
with the acid to be employed. The tube may then be warmed, so as
to bring the acid gently to the boiling-point, over the flame of a
small spirit lamp or Bunsen burner. Or, in place of the test-tube, a
small porcelain capsule, provided with a short handle, may be used.
In the examination of minerals for the presence of earths and
alkalies, a small direct-vision spectroscope will be found very service-
able. The small pocket spectroscopes, 3J inches long, with attached
scale, made by Browning of London, cannot be too highly recom-
mended. Many minerals (Calcite, Gypsum, Polyhallite, Strontianite,
Celestine, Barytine, Lepidolite, &c., &c.) give characteristic spectra by
sufficiently prolonged ignition in the outer border of a Bunsen flame,
but the reaction becomes in most cases greatly intensified by moisten-
ing the ignited substance with hydrochloric acid, as described at
page 55 and in many of the following Tables. In the Tables proper,
all, or practically all, known species are inserted ; but each Table is
followed by an Explanatory Note, in which the commonly occurring
or important species of the Table are alone referred to. In these
notes, crystallographic and other distinctive characters are given in
somewhat greater detail.
INDEX TO THE TABLES.
A.-THE MINERAL PRESENTS A METALLIC LUSTRE.
A1. — A small fragment ignited, BB, on charcoal volatilizes wholly or partly.
(1) It gives As fumes, but no sulphur-reaction with carb. soda TABLE I.
(2) It gives As fumes and sulphur-reaction TABLE II.
(3) It gives reaction of Sulphur or Selenium, but no fumes of Sb or Te.
TABLE III.
(4) It gives sulphur- reaction, and fumes of Sb or Te TABLE IV.
(5) It gives fumes of Sb or Te, but no sulphur-reaction TABLE V.
(6) It gives no reaction of S, Se, Te, Sb, or As TABLE VI.
A2. — A small fragment ignited on charcoal does not perceptibly volatilize.
(1) It fuses, BB, on charcoal into a globule , . . TABLE VII.
(2) It is infusible, or fuses only on the thin edges TABLE VIII.
B.— THE MINERAL PRESENTS A SUB METALLIC ASPECT.
(1) It is easily fusible or reducible per se TABLE IX.
(2) It is infusible, or fusible only on thin edges TABLE X.
C.-THE MINERAL PRESENTS A VITREOUS, PEARLY, EARTHY,
OR OTHER NON METALLIC ASPECT.
C1.— A small fragment takes fire when held against a candle or Bunsen-flame.
(1) It burns with blue flame and sulphurous or alliacceous odour. . TABLE XI.
(2) It burns with bituminous or aromatic odour TABLE XH.
C2. — The mineral is not inflammable. It is readily dissolved or attacked
by fusion with borax or phosphor-salt.
(1 ) It is attacked with effervescence by dilute hydrochloric acid, TABLE XIII .
(2) It emits As fumes by fusion with carb. soda on charcoal TABLE XIV.
(3) It emits Sb fumes by fusion with carb. soda on charcoal TABLE XV.
(4) It gives sulphur-reaction with carb. Jjda TABLE XVI,
ICO INDEX TO THE TABLES.
(5) Its solution in nitric acid* gives a canary-yellow pre. with molyb-
date of ammonia TABLE XVII
(6) Its powder, moistened with sulphuric acid and alcohol, communi-
cates a green colour to the flame of the latter TABLE XVIII.
(7) It gives chlorine (I or Br) reaction (azure or green flame) by fusion
with phosphor-salt and copper oxide TABLE XIX,
(8) It evolves orange-red fumes when warmed with a few drops of
sulphuric acid in a test-tube TABLE XX,
(9) It corrodes the glass when warmed in powder with sulphuric acid
in a test-tube TABLE XXI.
(10) It forms by fusion with carb. soda and nitre an alkaline mass
partly soluble in water, the solution assuming a blue, brown,
or green colour when boiled with addition of hydrochloric
acid and a piece of tin or zinc TABLE XXII.
(11) It does not produce any of the above reactions TABLE XXIII,
C3. — The mineral is very slowly dissolved, or is only partially attacked, BB, by
borax or phosphor-salt.
t It is infusible, or fusible only on the thinnest edges :
(1) It is hard enough to scratch ordinary glass distinctly, TABLE XXIV.
(2) It is not hard enough te scratch glass distinctly .... TABLE XXV .
ft It is more or less readily fusible :
(1) It yields no water (or merely traces) by ignition in bulb-
tube TABLE XXVI.
(2) It gives off a distinct amount of water by ignition in bulb-
tube TABLE XXVII.
NOTE. — In order to appreciate the distinctive character of the respective sections C2 and C3,
the student is recommended to add a small fragment of calcite, gypsum, fluor spar, barytine,
or apatite, on the one hand, — and a small particle of orthoclase, pyroxene, amphibole, garnet,
talc, quartz, or corundum, on the other — to a previously fused bead of phosphor-salt ; and to
observe the rapidity with which the first-named minerals are dissolved under the action of the
blowpipe, whilst the minerals of the latter group remain practically unaffected, or are very
slowly or incompletely attacked.
* Crush a small fragment of the substance to powder. Place this, by a bent slip of paper,
in a test-tube. Drop a little nitric acid upon it, and warm or boil. Then add some distilled
water and a grain or two of the molybdate, and warm again.
TABLES
FOE THE DETERMINATION OF MINERALS.
TABLE I.
[Metallic aspect. Wholly or partly vol. with As fumes, but yielding no
S reaction.]
A.— Entirely vol. (or leaving merely a feeble residuum).
NATIVE ARSENIC: Hemi-Hex. ; H 3-5 ; G 6-0 ; tin-white with dark
tarnish.
Allemontite : differs merely by having part of the As replaced
bySb.
NATIVE BISMUTH — ARSENIC-HOLDING VARIETIES. G 97, BB, a
yellow deposit on charcoal. See TABLE VI.
B.— Partially vol., leaving distinct residuum.
Bi.— RESIDUUM MAGNETIC.
SMALTINE: (CoNiFe) 28, As 72. Keg.; H 5-5-6; G 6-5; greyish
tin-white. Chloanthite (Chathamite) is a highly nickeliferous smal-
tine. Skutterudite is probably a mixture of smaltine and arsenic
( = CoAs2 -f As).
LOLLINGITE : Fe 27-2, As 72-8. Rh. ; H 5-5-5 ; G 7-7-4 ; greyish
silver-white. Leucopyrite (Fe 32-2, As 66-8 (?) ) is closely related.
In both, a little S is often present. (See below).
B2.— RESIDUUM NOT MAGNETIC.
(Ni reaction).
RAMMELSBERGITE : Ni (CoFe) 28, As 72. Rh. ; H 5-5 ; G 7-1 ;
greyish silver- white.
NICKELINE: Ni (Fe,&c.) 43-6, As56-4. Hex.; H 5-5; G>5-7'7;
pale copper-red.
(Cu reaction).
DOMEYKITE: Cu 71-7, As 28-3 ; H 3-3-5 ; G 7-7-5 ; silver-white
or tin-white, tarnished. ALGODONITE (Cu 83*5, As 16-5) and WHIT-
NEYITE (Cu 88-4, As 11-6) are closely related, but with higher sp. gr.
(8-8-3).
•102 BLOWPIPE PRACTICE.
(Ag reaction).
RITTINGERITE : Normally, AgAs (?) with 57'7 Ag, but commonly
contains sulphur. Iron-black, red by transmitted light; streak
orange-yellow, lustre, mostly, sub-metallic. Clino-Rh. ; H 2-5-3 >
G 5-63. (See TABLE IX).
NOTE ON TABLE I.
The only minerals of general occurrence belonging to this Table are Native
Arsenic, Smaltine, and Nickeline. N. Arsenic is commonly in botryoidal
masses with dark surface-tarnish, and is readily distinguished BB by volatilizing
rapidly without fusing. Smaltine occurs most frequently in small tin-white
octahedrons of sufficient hardness to scratch glass, but is also found in reticu-
lated groups of minute indistinct crystals, and massive. After roasting, the
smallest particle imparts BB a rich blue colour to borax. Nickeline is rarely
found otherwise than massive. Its light copper-red or yellowish-red colour
and high sp. gr. are its more salient characters. BB, it melts easily into a
hard brittle non-magnetic globule with crystalline surface. The globule
remains non-magnetic after long exposure to the flame.
[103]
TABLE II.
[Metallic aspect. As and S reactions.]
A.— Residuum magnetic.
(Co reaction).
COBALTIXE : Co (Fe, &c.) 35-5, As 45-2, S 19-3. Reg. H 5-5 ; G
6 '3; silver-white, greyish.
GLAUCODOT: (GoFe) 35, As 45-5, S 19-5. Rh. ; II 5-5, G 6-2;
silver-white, greyish. Strictly, a cobaltic Mispickel.
(Ni reaction).
GERSDORFFITE : Ni 35, As 45-5, S 19-5. Reg. ; H 5 -5 ; G 6-6-3 ;
greyish tin- white.
ULLM ANNITE : essentially antimonial : See TABLE IV. Corynite,
with more As than Sb, is closely related. Also Wolfachite, but the
latter is Rhombic in crystallization.
(Fe reaction).
MISPICKEL or ARSENICAL PYRITES : Fe 34*4, As 46, S 19'6. Rh. ;
H 5-5-6; G 6-0-6-3; silver- white, greyish. GLAUCODOT and DANAITE
are cobaltiferous varieties. ALLOCLASE is a related steel-grey species,
containing Co, Ni, Bi, &c. GEIERITE is also a related compound,
but with higher percentage of arsenic ( = Fe 33'6, As 60, S 6*4).
PLINIAN is apparently a clino-rhombic mispickel.
LOLLINGITE : — LEUCOPYRITE : Normally, iron arsenides free from
sulphur, but frequently mixed with a little FeS2. See TABLE I.
(Cu reaction).
TENNANTITE (Arsenical . Tetrahedrite) : Cu, Fe, As, S, with Cu
averaging 50 p. c. Reg.; H 3-5-4-0 ; G 4'4-4'5 ; dark lead-grey, iron-
black. Some examples of Tetrahedrite, proper, contain traces of As.
See TABLE IV.
B.— Residuum non- magnetic-
(Cu reaction).
ENARGITE: Cu 48-5, As 19, S 32'5. Rh. ; H 3 ; G 4-44; dark-
grey, iron-black. -Epigenite is closely related, but contains some
iron. Also Clarite and Luzonite.
COPPER BINNITE ( = Dufrenoysite of Damour, Kengott, &c.) Cu
39, As 31, S 30. R3g. ; H 25 ; G 4-6 ; dark ste^l-grey, brownish-
black; streak, red-brown.
104 BLOWPIPE PRACTICE.
(Ag reaction).
POLYBASITE (arsenical variety, see TABLE IV.) gives large silver-
globule by cupellation. Iron-black; red in thin pieces by transmitted
light.
RITTINGERITE : normally, Ag As, but sulphur commonly present.
Iron-black, red by transmitted light; streak orange-yellow. See
TABLES I., IX., XIV.
(Pb reaction).
DUFRENOYSITE (v. Rath): Pb 57, As 21, S 22. Rh. ; H3; G
5-5-5-6 ; dark lead-grey, streak red-brown. Jordanite is nearly
related. Pb 51, As 25, S 24.
LEAD-BINNITE ( = Binnite of Heusser, Scleroclase of V. Walters-
hausen, Sartorite of Dana) : Pb 427, As 31, S 26'3. H 3; G 54;
dark lead-grey, streak red-brown.
GEOCRONITE (occasional varieties, but the species is essentially auti-
monial. See TABLE IV.)
NOTE ON TABLE II.
Cobaltine, Mispickel, and Tennantite, are the only minerals of ordinary
occurrence belonging to this Table. Cobaltine is commonly in small crystals
of a silver- white colour with slightly reddish tinge. These crystals are most
commonly combinations of the cube and pentagonal dodecahedron °°2, the
lafctor predominating ; or combinations of this pentag. dodecahedron with the
octahedron. The crystals scratch glass easily. More rarely, cobaltine occurs
massive, The smallest particle, after roasting, imparts BB a deep-blue colour
to borax,
Mispickel or Arsenical Pyrites} occurs commonly both in masses and in
small prismatic crystals of the Rhombic System, Its colour is silver-white,
but the surface soon assumes a greyish or other tarnish. The crystals, which,
as a rule, scratch glass distinctly, are mostly rhombic prisms (with V : V —
111° 12') terminated by two nearly flat and transversely striated planes (the
brachydome or side-polar £ P, with summit angle = 146° 28'). It fuses easily,
with emission of copious arsenical fumes, and the fused globule (after sufficient
exposure to the flame) attracts the magnet strongly. Many varieties contain
cobalt, and in some, nickel is present. Nearly all varieties, moreover, hold a
certain amount of gold or silver, varying from a few clwts. to several ounces
per ton.
Tennantite is readily distinguished from the above by its dark colour and
low degree of hardness, as well as by its strong copper-reaction. It occurs
only in small crystals of the Regular System : mostly tetrahedral combinations,
or these associated with the rhombic dodecahedron or cube.
[105]
TABLE III.
[S or Se reaction. No fumes of As, Sb, or Te.]
A— Fusible: fusion-product magnetic.
(Co and Ni reactions).
LINN^ITE (ZiEGENiTE): (Co, NiFe) 58, S 42. Reg.; H 5-5; G 4-9;
light steel-grey with reddish tarnish.
(Ni reaction).
MILLERITE: Ni 35-5, S 64-5. Hemi-Hex., acicular; H 3; G 5-3
(4*6 Kengott). Brass or bronze-yellow.
POLYDYMITE: Ni 59-5, S 40-5. Reg.; H 4-5 ; G4-81; lead grey.
SAYNITE is this species mixed with copper pyrites, galena, &c. BEYRI-
CHITE is closely related.
(Fe reaction),
IRON PYRITES (MUNDIC) : Fe 46-7, S 53-3. Reg. ; H 6-6-5 ; G
4-8-5-2 ; pale brass-yellow. (See Note, below).
MARCASITE : Rhombic in crystallization ; otherwise like ordinary
Pyrites.
PYRRHOTINE (MAGNETIC PYRITES): Fe 60-5, S 39-5. Hex.; H
3-5-4-5 ; G 4-4-47; bronze-yellow; magnetic. Horbachite is a
nickeliferous var. ; Troilite, a meteoric pyrrhotine.
(Cu reaction).
COPPER PYRITES (Chalcopyrite) : Cu 34-6, Fe 30-5, S 34-9. Tetr. ;
H 3-5-4; G 4-1-4-3; rich brass-yellow, often with variegated tarnish;
streak greenish-black, or dark-green. HOMICHLINE is apparently a
mixture of this sp. and the next. BARNHARDTITE is also closely
related.
BORNITE (Purple Cop. Pyrites, Buntkupfererz) : consists of Cu.
Fe, S in somewhat variable proportions. The Cu averages 50-60
p. c. Many analyses shew: Cu 55 6, Fe 16-4, S 28. Reg.; H 3;
G 4-5-5-2; brownish copper-red, rapidly tarnishing blue, green, &c. ;
streak black.
CUBANITE: Cu 20, Fe 41, S 39 (?). Reg. ; H 4; G 4-1 ; brass-
yellow, streak black.
STANNINE (Tin Pyrites). Fusion-globule in some cases magnetic.
See B2.
106 BLOWPIPE PRACTICE.
B — Fusible : fusion product non-magnetic.
B». -EVOLVING, BB, STRONG ODOUR OF SELENIUM.
(Cu reaction).
BERZELINE : Cu 61-6, Se 38-4. In thin coatings; very soft; silver-
white, tarnishing black.
CROOKESITE : Cu 45-76, Th 17-25, Ag 3-71, Se 33-28. Compact;
H 2-5-3 ; G 6-9 ; lead-grey. Colours flame intensely green.
EUKAIRITE : Ag 43-1, Cu 25-3, Se 31-6. Soft, lead-grey.
ZORGITE : Cu, Pb, Se, in variable proportions. Lead-grey, soft.
Comprises, probably, several distinct species.
(Pb or Bi reaction).
CLAUSTHALLITE : Pb 72-4, Se 27'6. Keg.; H 2-5-3; G 8-8-8;
lead-grey.
NAUMANNITE: Ag (Pb) 73, Se 27. Beg.1; H 2-5 ; G 8-0; iron-
black. BB, yields large bead of silver.
LEHRBACHITE: contains Pb and Hg, with Se. H 2-5; G 7*9;
lead -grey.
GUANAJUATITE : Bi 69-7, Se (S) 30-3. Apparently Rhombic, but
very imperfectly known. Silaonite is a related compound. TETRA-
DYMITE : Essentially a bismuth telluride, but sometimes contains Se
and S. Refer to TABLES IV., V.
(Hg reaction).
TIEMANNITE: Hg 75, Se 25. H 2-5 ; G 7-7-4; dark lead-grey.
BB, rapidly volatilized. Onofrite is an allied compound of Hg, Se,
and S. Guadalcazarite, a sulphide of Hg and Zn, has part of its S
replaced by Se, and should therefore be referred to here. It is iron-
black in colour, with H 2, and G 7-15.
B2.—NO SELENIUM ODOUR EVOLVED ON IGNITION.
(Cu reaction).
CHALKOSINE (Copper Glance): Cu 79-8, S 20-2. Rh. ; H 2-5-3-0;
G 5-5-5-8. Dark metallic-grey, usually with green or blue-green
tarnish.
STANNINE (Tin Pyrites): Cu, Sn, Fe, &c., S. Reg.; H 3-5-4;
G 4-4 ; yellowish steel-grey. Decomposed by nitric acid, leaving
residuum of SnO2.
STROMEYERINE: Ag53,Cu 31-3, S 15-7. Rh.; H 2-5-3-0; G 6-25.
Blackish lead-grey. BB, by cupellation, gives large silver-button.
\
MINERAL TABLES I — III. 107
ZALPAITE: Ag 71*8, Cu 14, S 14-2. Keg. ; H 2-2-5; G 6-9.
Blackish lead-grey ; ductile.
(Cu and Pb or Bi reaction).
AIKINITE (Needle Ore): Cu 11, Pb 36, Bi 36, S 17. Rh.; II 2-5;
G 67. Dark-lead or steel grey, with yellowish or other tarnish.
Mostly acicular in quartz.
WITTICHENITE: Cu 38-5, Bi 42, S 19-5 (1). Rh.; H 2-5; G 4-3-4-6.
Dark metallic-grey.
EMPLECTITE: Cu 19, Bi 62, S 19. Rh. ; H 2-2-5; G 5-2; tin-
white, yellowish. Acicular in quartz.
CUPRO-PLUMBITE: Cu 20, Pb 65, S 15 ( = Cu2S + 2 PbS). Massive,
with cubical cleavage; dark lead grey. H 2-5 ; G 6-4. ALISONITE
is a related compound, but with more copper ( = 3 Cu2S -h PbS).
(Pb or Bi reaction).
GALENA (Lead Glance) : Pb 86'6, S 13-4. Reg. ; cleavage cubical;
H 2-5; G 7-3-7-6. Lead-grey.
BISMUTHINE (Bismuth Glance): Bi 81-25, S 18-75. Rh.; H 2-2-5;
G 6-4-6-7. Light metallic-grey, often iridescent.
COSALITE : Pb (Ag) 41-7, Bi 42-2, S 16*1 ; Lead-grey; H abt. 2-0.
Retzbanyite, a related compound.
(Ag reaction).
ARGENTITE (Silver Glance) : Ag 87, S 13. Reg. ; H 2 ; G 7-2-7-4.
Blackish lead-grey, iron-black ; malleable. ACANTHITE has the same
composition, but is Rhombic in crystallization.
#*# See, also, the Cu-Ag sulphides, Stromeyerine and Zalpaite,
above.
(Hg reaction).
METACINNABARITE : Hg 86-2, S 13-8. Black, streak black. G 7-7.
H 1-5-2. Guadalcazarite is identical or closely related.
C.— Infusible, or Fusible on edges only.
(Mo reaction. Flame tinged pale-green).
MOLYBDENITE : Mo 59, S 41. Hex. 1 ; H 1-1 -5 ; G 4-4-4-8. Light
lead-grey. Mostly in flexible plates and scaly masses, which mark on
paper and otherwise much resemble graphite, but easily distinguished
by communicating a distinct yellowish -green colour to the outer
flame, as well as by sulphur reaction, and higher sp. gr.
108 BLOWPIPE PRACTICED
(Zn reaction).
SPHALERITE or ZINC BLENDE : Some varieties, only, are metallic or
sub-metallic in lustre. Streak pale-brown. See TABLES X. and XVI.
(Mn reaction),
ALABANDINE : Mil 63-2, S 36-8. Black, brownish, dark steel-grey.
Streak greenish. Lustre sub-metallic. See TABLE X.
HAUERITE: Mn 4 6 '2, S 53-8. Dark red-brown, blackish-brown.
Streak brownish. Lustre sub-metallic, only. See TABLE X.
NOTE ON TABLE III.
The minerals of comparatively general occurrence belonging to this Table,
although more numerous than those of Table II., do not exceed ten or eleven
in number. They may be arranged, as regards determination, under two
leading groups, according to colour. In the first group, the colour is some
shade of metallic yellow or red ; and in the second, metallic grey or black.
The first group includes Iron Pyrites, Marcasite, Pyrrhotine, Copper Pyrites,
and Bornite. The second group includes Argentite, Molybdenite, Galena,
Bismuthine, and Chalkosine, with, exceptionally, certain dark varieties of
Zinc Blende, in which the lustre inclines to metallic.
(Colour pale brass-yellow : H — 6'0 or more).
Iron Pyrites and Marcasite belong to this section : they are sufficiently hard
to scratch glass distinctly. Iron Pyrites occurs both massive and in crystals.
The latter are commonly cubes (with faces marked by alternate striae), or
combinations of cube and octahedron, or combinations of the cube and the
pentagonal dodecahedron 2Q° , or this pentag. dodecahedron alone. Marcasite
presents the same composition (FeS2), but differs by its Khombic crystallization,
and its greater tendency to fall into decomposition. The crystals are com-
monly flat prismatic combinations, with largely developed basal plane, and
V : V = 106°5' ; and they are frequently in twinned forms, or grouped in crested
rows ; whence the name "spear pyrites," "cockscomb pyrites," etc., applied
to the species.
(Colour brass -y Mow, bronze-yellow, or reddish: H under 5*0).
Pyrrhotine or Magnetic Pyrites, Copper Pyrites, and Bornite, belong to this
section ; none scratch glass. Pyrrhotine is bronze-yellow, almost always
massive, and more or less magnetic, sometimes showing polarity. Copper
Pyrites is rich brass-yellow, often with variegated tarnish ( = "Peacock Ore,"
etc.), and its streak is blackish-green. It is commonly massive; but occurs
also in Tetragonal crystals, mostly small tetrahedrons or sphenoids, much
resembling regular tetrahedrons. Bornite or Purple Copper Pyrites has pro-
perly a peculiar reddish colour (whence "horse-flesh ore"), but this becomes
rapidly obscured by a blue or green tarnish. It is nearly always massive, and
its streak is black without any shade of green in the colour.
MINERAL TABLES : — HI. 1 09
(Colour metallic grey or black: flexible in thin pieces, or malleable).
This section includes Argentite and Molybdenite. Argentite is at once dis-
tinguished by its dark colour and its malleability > as well as by its high sp.
gr. (over 7'0), and by yielding, BB, a large silver-globule. When crystallized,
it is mostly in combinations of cube, octahedron, and rhombic dodecahedron,
but the crystals #re commonly distorted. It occurs also frequently in leafy
and filiform examples. Molybdenite is light lead-grey, mostly in scaly or
leafy masses, very soft and flexible, but not malleable. It is readily dis-
tinguished by the yellowish-green colour which it communicates to the outer
edge of the Bunsen or blowpipe flame, and by its infusibility. It forms, BB,
011 charcoal a white deposit of MoO3.
(Colour metallic grey or black : BB, on charcoal a yellow deposit).
This section includes Galena and Bismuthine,— the first of very common
occurrence, the latter comparatively rare. Galena is distinguished by its
rectangular or cubical cleavage, and its high sp. gr. ( = 7 '3-7 '7). When
crystallized, it is commonly in cubes or in combinations of cube and octahedron.
The fusion-globule is malleable, and it generally yields a little silver on cupel-
lation. Bismuthine is mostly in fibrous masses or acicular crystals. It melts,
if held (in the form of a thin splinter) against the outer edge of the flame,
without the application of the blowpipe. Its nitric-acid solution yields a white
precipitate on the addition of water.
(Colour blackish metallic-grey. Surface usually encrusted here and there with a
greenish, earthy efflorescence. )
This section (as regards minerals of common occurrence) contains Chalkosine,
Cu2S, only. Easily distinguished by its marked copper-reactions. Forms
BB no coating on charcoal, but boils, spirts, and yields a copper-globule.
Commonly massive. When crystallized, mostly in small, Rhombic com-
binations of pseudo-hexagonal aspect.
(Colour black or brownish-black. Lustre properly sub-metallic. Streak pale-
brown. Infusible, or practically so).
Certain dark varieties of Zinc Blende (Black Jack) may be referred to here,
as these are sometimes mistaken for galena.* Their infusibility, brownish
streak, and comparatively low sp. gr. ( =• about 4*0), constitute their more
distinctive characters. Mixed, in powder, with carb. soda and a little borax,
they yield, BB, on charcoal a ZnO sublimate.
* A practical illustration of this came under the author's notice in Colorado a few years ago.
He was asked to look at a somewhat roughly constructed reverberatory that had been recently
jtut up for the smelting of lead ore, but which had turned out a failure. The ore, it appeared,
got into a pasty mass holding a little reduced lead, and would not work. After examining the
furnace, and seeing nothing particularly amiss in'it, the writer asked to look at the ore This
was regarded at the furnace as a tolerably clean galena, but was found to consist of nearly two-
thirds " Black Jack " mixed with galena in a calcareous gangue. The " pasty stuff" which had
:-riven the furnace a bad name was thus easily accounted for. The old name Blende (and the
newer Sphalerite) is based on this deceptive aspect. In general, however, the lustre is non-
metallic, or at most, sub-metallic.
[110]
TABLE IV.
[S reaction. Sb or Te fumes.]
A.— On charcoal, BB, a white deposit.
Al.— ENTIRELY AND RAPIDLY VOL.
STIBNITE (Antimony Glance, Grey Antimony Ore): S 28-24,
Sb 7176. Rh ; H 2; G 4-5-4-7. Lead-grey, often with iridescent
or dark tarnish. Melts per se in outer edge of the flame without the
aid of the blowpipe. See also the note below.
CINNABAR (HgS). Some dark or lead-grey varieties. Streak red;
G 7 '7-9. Inflammable. Lustre, as a rule, non-metallic. (See
TABLE XI).
AS.— PARTIALLY VOL., A LARGE SILVER-GLOBULE REMAINING.
(The minerals of this section present as a rule a sub-metallic aspect. The
three first are slightly translucent in thin pieces, and have a red streak).
MIARGYRITE: S 21-8, Sb 41-5, Ag 36-7. Clino-Rh. ; H 2-2-5;
G 5-18-5-26. Iron-black, streak dull-red.
PYRARGYRITE (Dark Red Silver Ore): S 17-7, Sb 22-5, Ag 59-8.
Hemi Hex. ; H 2-2-5 ; G 5-75-5-85. Iron-black, reddish, streak red.
POLYBASITE : S, Sb (As), Ag 64-74 p. c. ; Cu sometimes present.
Rh. ; H 2-5 ; G 6-0-6-2. Iron-black; streak, black, red. Polyargy-
rite is closely related, but is Regular in crystallization.
STEPHANITE (Melanglanz, Brittle Silver Ore): S, Sb (As), Ag (Cu)
68 p. c. H Rh. ; H 2-5 ; G 6-3. Iron-black, dark lead-grey, often
iridescent.
A3.— PARTIALLY VOL , THE RESIDUUM MAGNETIC.
BERTHIERITE: Average comp. S 30, Sb 57, Fe 13. Rh. (?);
H 2-5-3 ; G 4-4-3. Dark steel-grey, often with variegated tarnish.
ULLMANNITE (Antimonial Nickel Glance): S 15, Sb 57'5, Ni 27-5.
Reg. ; H 5-0-5-25 ; G 6-2-6-5 ; lead-grey or steel-grey, with dark or
variegated tarnish. Some examples are arsenical.
A*.— PARTIALLY VOL., THE RESIDUUM GIVING STRONG COPPER-REACTION.
TETRAHEDRITE (Grey Copper Ore ; Fahlerz) : S, Sb (As), Cu 33-44
p. c., Ag, Fe, <fec. Reg. (tetrahedral); H 3-4; G 4-8-5-4. Steel-
grey, iron-black.
MINERAL TABLES: — iv. Ill
CHALKOSTIBITE (Wolfsbergite) : S 25-7, Sb 25-4, Cu 48-9. Eh.;
H 3-5 ; G 4*7-5 ; dark lead-grey, iron-black, often with variegated
tarnish.
B.—On charcoal, BB, a yellow (or white and yellow) deposit.
B'.— PARTIALLY VOL , A GOLD OR SILVER GLOBULE FINALLY REMAINING.
(If the blowing be stopped too soon, a rich gold-lead or silver-lead globule
will of course result. This may be freed from lead on the cupel).
FREIESLEBENITE (Donacargyrite). S 18-8, Sb 26*9, Ag 23-8,
Pb 30-5. Clino-Rh. H 2-2-5 ; G 6-2-6-5 ; metallic grey. Diapho-
rite (v. Zepharovich) from Przibram is closely related, but is Rhombic
in crystallization. G 5 -9.
BRONGNIARDITE : S 19-5, Sb 29-5, Ag 26, Pb 25. Reg. ; H 2-5 ;
G 5 -9-6 -0 ; dark metallic-grey.
NAGYAGITE (Leafy Tellurium Ore, Blattererz) ; S, Te, Pb, An,
Ag, &c. An, commonly, 6-9 p. c. Tet., but mostly in thin flexible
laminae. H 1-1*5 ; G 6'8-7'2. Blackish lead-grey. Melts per se in
edge of candle-flame.
B2.— PARTIALLY VOL., THE RESIDUUM GIVING STRONG COPPER-REACTION.
BOURNONITE: S 19-66, Sb 24-98, Pb 42-38, Cu 12-98. Rh. ;
H 2-5-3 ; G 5-7-5-9. Dark steel-grey, iron-black.
See also Tetrahedrite, some examples of which contain Pb or Bi ;
and Zinkenite and Jamesonite, which sometimes contain a small
percentage of copper.
B3.— PARTIALLY VOL., BUT GIVING NO MARKED REACTION OF Ag, Au, or Cu.
(Sp. gr. under 6'0).
ZINKENITE: S 22, Sb 42, Pb 36. Rh., acicular; H 2 -5-3 -5 ;
G 5-3-5-4. Steel-grey, lead-grey, often with variegated tarnish.
PLAGIONITE: S 21, Sb 37, Pb 42. Clino-Rh.; H 2-5; G 5'4.
Dark lead-grey.
JAMESONITE: S19-6; Sb 29-8, Pb 50-6. Rh. H2-5; G 5-5-5-62.
Metallic-grey. Cleavage basal, strongly marked.
BOULANGERITE: S 18, Sb 23, Pb 59. Crystn.?; H 2-5-3 ; G 5-7-5 -95.
Dark lead-grey.
(Sp. gr. over 6'0).
MENEGHINITE: S 17-3, Sb 18-8, Pb 63'9. Clino-Rh., acicular.
H 2-5-3; G 6-34-6*4. Lead-grey. Some examples appear to be
Rhombic in crystallization,
112 BLOWPIPE PRACTICE.
GEOKRONITE : S, Sb, Pb 65 p. c. Some examples contain also a
little Cu. Rh. ; H 2-3 ; G 6-44-6-54; lead-grey, tarnishing darker.
Kilbrickenite is identical or closely related.
KOBELLITE : S 16-8, Sb 107, Pb 54*3, Bi 18-2. Crystal. ?; H 2-5;
G 6-15-6-30. Dark lead-grey.
TETRADYMITE : Normally, a compound of Bi and Te, but frequently
containing small amounts of S or Se. Light steel-grey. H 1-3 ;
G 7 "4-7 -9; flexible in thin pieces. Wehrlite is a var. containing S.
Some vars. also contain a small percentage of Ag. See TABLE V.
NOTE ON TABLE IV.
The only minerals of common or general occurrence belonging to this Table,
comprise: Stibnite, Tetrahedrite, Pyrargyrite, Bournonite, Zinkemte, and
Jamesonite.
Stibnite or Antimony Glance (also known as Grey Antimony Ore) is dis-
tinguished (if pure : id est, if unmixed with lead sulphide, &c. ) by its rapid
volatilization before the blowpipe ; and by its powder becoming orange-yellow
in a hot solution of caustic potash. It is generally in masses of a more or less
fibrous structure and light lead-grey colour, or in small Rhombic prisms (with
V : V — 90°54') terminated by the planes of a rhombic octahedron. The prism-
planes are longitudinally striated, but the crystals are usually acicular or more
or less indistinct. The only species which somewhat resemble it are the sul-
phantimonites Zinkemte, Jamesonite, Bournonite, &c., but these give a lead
sublimate on charcoal, and Boumn'-1 gives also a strong copper-reaction.
They are attacked but not rendered y.Jow by caustic potash, but an orange
precipitate is thrown down if the potash solution be neutralized by hydro-
chloric acid. Jamesonite is chiefly distinguished by its ready cleavage in one
direction ; and Bournonite by its copper-reaction. The latter mineral is often
found in small, flat, Rhombic crystals with largely developed basal plane, and
V : V = 93°40'. These crystals are frequently in cruciform or other twins. .
Tetrahedrite is dark-grey or iron-black in colour, and when crystallized is
in small tetrahedrons or tetrahedral combinations. It gives strong copper-
reactions, and some examples (Rionite) contain zinc ; others, silver, mercury, &c.
Pyrargyrite or Dark Red Silver ore is iron-black or reddish lead-grey in
colour, except in thin pieces by transmitted light, when the colour appears
blood- red. The streak is red ; and the crystals are mostly combinations of the
hexagonal prism with the planes of one or two rhombohedrons (R : R — 108°42' ;
\ R : \ R = 137° 58'), but the mineral is most commonly massive or in indis-
tinct crystal aggregations. It melts per se in the outer edge of the flame with-
out the aid of the blowpipe. On charcoal, BB, a silver globule is easily
obtained. Like other sulphantimonites, it is attacked by hot caustic potash,
and hydrochloric acid precipitates orange-red Sb2S3 from the solution.
[113]
TABLE V.
[Metallic Aspect. Sb or Te fumes, but no S reaction.]
A.— Entirely volatilizable, or leaving merely a minute
globule of metal.
Ai.— ON CHARCOAL, BB, A WHITE DEPOSIT.
NATIVE ANTIMONY: Hemi-Hex., cleavable ; H 3-3-5 ; G 6*7 ; tin-
white. Converted by nitric acid into yellowish- white powder (Sb2O3 +
Sb*O*).
NATIVE TELLURIUM: Hemi-Hex., cleavable; H 2-2-5 ; G 6-1-6-3;
tin-white. Soluble in nitric acid. Warmed with strong sulphuric
acid (the acid being used in excess) forms a purplish-red solution,
which becomes colourless on addition of water — metallic Te falling
as a dark-grey precipitate. Forms also a red solution when boiled in
powder with caustic potash.
A*.— ON CHARCOAL, BB, A YELLOW (OK WHITE AND YELLOW) DEPOSIT.
TETRADYMITE : Bi 52, Te 48, but S and Se often present in small
proportions. Hemi-Hex.; H 1-5-2; G 7 '4-7 '9; pale metallic-grey;
flexible in thin pieces.
ALTAITE: Pb 61-2, Te 38*8. Reg.; H 2-5-3-5; G 8 1-8-2; tin-
white, yellowish.
B —Partially volatilizable.
B».— YIELDING, BB, OX CHARCOAL A LARGE GLOBULE OP Ag OR Au.
DYSCRASITE : Ag and Sb in several proportions : Ag 64-84, Sb
15-8-36. Rh. ; H 3*5 ; G 9-4-10. Silver-white or tin- white, with
dark or yellowish tarnish.
HESSITE: Ag 62-8, Te 37-2. Rh. ; H 2-3*0; G 8-1-8*5. Dark
metallic-grey. Petzite is a closely related mineral, but with a large
part of the Ag replaced by Au (G 8 '7-9 -4).
SYLVANITE (Graphic Tellurium): Ag, Au, Te, in variable propor-
tions. Sb and Pb also present in some examples, Au 25-45, Ag l-lo,
Te 45-56. Glino-Rh. (or Rh. ? ); H 1-5-2; G 8-8*4. Light steel-
grey inclining to silver-white or pale yellowish. Calaverite is a
yellow var., with Au 44-5, Te 55-5. Miillerine is also an auriferous
var,, containing Pb and Sb in addition to the normal components.
114 BLOWPIPE PRACTICE.
B«. -YIELDING, BB, A MAGNETIC (NICKELIFEROUS) GLOBULE.
BREITHAUPTITE (Antimonial Nickel Ore): Ni 32'2, Sb 67'8. Hex. ;
H 5 ; G 7 '5-7 '6 ; pale copper-red, mostly with bluish tarnish. Com-
monly massive, or in small tabular crystals with striated base.
Isomorphous with Nickeline, TABLE I. Part of the Ni usually
replaced by Fe.
MELONITE : Ni 23-5, Te 76'5. Hex. ? Pale reddish-white.
NOTE ON TABLE V.
All the minerals of this Table are of exceptional or merely local occurrence.
Those which contain gold or silver are easily recognized by the metallic
globule which they yield, BB, on charcoal. The presence of antimony is
revealed by the copious fumes emitted, BB ; and by the formation of a
yellowish-white powder (SbW or Sb205, or a mixture of the two) in nitric acid.
The presence of tellurium, revealed by its blowpipe reactions, is readily con-
firmed by warming a small portion of the substance in a test-tube about half
filled with strong sulphuric acid, when a reddish solution will result. On
addition of water, a dark precipitate of metallic tellurium is thrown down.
[115]
TABLE VI.
[Aspect metallic. No S reaction. No fumes of As, Sb, or Te.]
A On charcoal, BB, no sublimate. (In closed tube, Hg
Reaction).
A*.— ENTIRELY VOL.
NATIVE MERCURY. In small fluid globules of a tin- white colour.
G 13-6.
A«. -PARTI ALLY VOL., A SILVER-GLOBULE REMAINING.
AMALGAM : Properly an isomorphous union of Ag and Hg : hence
these components are present in variable proportions. Keg. ; H 2-3'5 ;
G 10*8-1 4*10; brittle. Arquerite is a variety containing 86 J p. c.
silver. Kongsbergite, a var. containing 95 p. c. silver. Some
amalgams contain gold : in these the sp. gr. is usually 1 5 or more.
B.— On charcoal, BB, a yellow-sublimate.
Bi.— MALLEABLE.
NATIVE LEAD: Reg.; H 1-5; G 11 -3-1 1-4; lead-grey; ductile.
B2— CLEAVABLE (OR NOT MALLEABLE).
NATIVE BISMUTH: Hemi-Hex. H 2-5 ; G 9-6-9-8. Reddish
Silver- white, mostly with yellowish or variegated tarnish.
NOTE ON TABLE VI.
Native Bismuth and Native Amalgam are the only minerals of ordinary
occurrence belonging to this Table. N. Bismuth is readily distinguished by
its ( practical \y) complete volatilization before the blowpipe, with formation of
a yellow deposit of oxide on charcoal. It dissolves rapidly in nitric acid, the
solution yielding a white precipitate on the addition of water. Some varieties
contain traces of As, S, Te, &c. It occurs commonly in small cleavable
masses, but occasionally in dendritic and other examples. When crystallized,
it is mostly in small rhombohedrons with basal plane, the principal cleavage
being parallel with the latter. Amalgam is often in small crystals of the
Regular System, commonly in dodecahedrons or combinations of cube and
octahedron. In ordinary varieties the sp. gr. exceeds 13 '5. This latter
character, together with the large bead of silver which it yields, BB, and its
mercurial reaction, serve sufficiently to distinguish it*
[116]
TABLE* VII.
[Lustre metallic. Not perceptibly vol. Fusible on charcoal into a globule,]
A— Malleable.
NATIVE GOLD: Reg.; H 2-3; G 15-5-19-4. Gold-yellow, Not
attacked by nitric acid, nor by blowpipe fluxes. Always contains a
small amount of Ag.
NATIVE SILVER: Reg.; H 2-3; G 10'5 (or 10-11). Silver-white,
often with black surface-tarnish. Easily dissolved by dilute nitric
acid on heating : a white curdy pre. (turning dark-grey on exposure)
is formed by hydrochloric acid, or any soluble chloride, in the solution.
NATIVE COPPER: Reg.; H 2-5-3; G 8-5-8-9. Copper-red, often
with dull-brown tarnish. Easily sol. in nitric acid, forming a green
solution, which becomes deep-blue on addition of ammonia. The
fused bead blackens in the OF, its surface becoming encrusted with
CuO. This tinges the flame green.
B — Not malleable.
(Cu reaction).
CUPRITE (Red Copper Ore). Colour and streak red. Lustre
occasionally sub-metallic. (See TABLE IX).
TENORITE (Black Oxide of Copper): Cu 79-85, O 20-15. Rh. ? in
small, tabular crystals, massive, &c.; H 2-3 ; G 6-9-6-5. Steel-grey
to black. Melaconite is an earthy or scaly var., sometimes pseu-
domorphous.
O (Mn and Fe reactions.)
WOLFRAM. Brown, black. Lustre sub-metallic only. H 5-5-5 ;
G over 7. An iron-manganese tungstate. (See TABLE IX).
NOTE ON TABLE VII.
All the minerals of this Table, Tenorite excepted, are of tolerably common
occurrence. They are readily distinguished by the characters given above, or
by the following condensed scheme :
Malleable :
Colour yellow— N. Gold.
white — N. Silver.
" red — N. Copper.
Brittle :
Streak red— Cuprite.
" black or brown :
BB, Cu reaction — Tenorite.
" Mn reaction — Wolfram.
These ifiree latter minerals belong, properly, to other Tables. Exceptional varieties, only,
come under notice here.
[117]
TABLE VIII.
[Lustre metallic. Not perceptibly vol. Infusible'; or fusible at the extreme
point or edges, only.]
A— Not dissolved, BB, by borax or phosphor- salt.
A1.— VERY SOFT, BLACK, MARKING OR SOILING.
GRAPHITE (Plumbago). Normally, pure carbon : usually slightly
ferruginous, &c. Hex.; H 1-1-5; G- 1-9-2-3. Black, lustrous,
greasy-feeling.
A2.-MORE OR LESS MALLEABLE. SP. GR. OVER 11 (IN MOST CASES.
17 OR HIGHER).
NATIVE PLATINUM: Keg.; H 4-5; G 17-18. Silver- white, pale
steel-grey. Sol. in hot nitro-hydrochloric acid. Many examples con-
tain a small percentage of Fe, and thus act slightly or strongly on
the magnet. See under B1.
NATIVE IRIDIUM or PLATINUM-!RIDIUM : Ir, Pt, Rh, &c. Reg.
H 4'5-7; G 18-23, usually about 22. Greyish silver-white; scarcely
malleable. Insol. in nitro-hydrochloric acid.
'OSMIUM-IRIDIUM or NEWJANSKiTE. IrOs, mostly with the Ir in
excess. Hex.; H 6-5-7; G 19*5; tin-white. Emits disagreeable
odour of osmic acid when fused with nitre in closed tube.
IRIDOSMIUM or SYSSERSKITE : IrOs, with Os predominating.
G 21-21-2. Emits odour of osmic acid by ignition per se on char-
coal. Otherwise like Osmium-Iridium.
NATIVE PALLADIUM. Reg. H 4-5-5 ; G 11-8-12-2. Light steel-
grey or greyish tin-white. Malleable. Sol. in hot nitric acid, form-
ing a reddish solution.
B— Dissolved or readily attacked by fusion with borax or
phosphor-salt
B». -MAGNETIC BEFORE OR AFTER IGNITION.
(Malleable).
NATIVE IRON (Meteoric Iron): Fe combined in nearly all cases
with a certain percentage of Ni. Reg. ; H 4-5-5 ; t> 7-7-8 ; steel-
grey, iron-black.
PLATINUM-IRON: Pt with 10-20 p. c. Fe. Reg.; H 6; G 13-15.
Dark steel-grey. Properly, a ferruginous var. of Native Platinum.
118 BLOWPIPE PRACTICE.
Some examples (unless in fine filings) are not readily attacked by
borax. Some examples, also, are said to be non-magnetic.
(Brittle : i.e. not malleable).
MAGNETITE (Magnetic Iron Ore): Fe 72-4, O 27-6 ( = FeO, Fe'O),
Keg. ; H 5'5-6'5 ; G 4-9-5-2 ; iron-black, streak black ; often exhibits
magnetic polarity. Magno-ferrite (better named Ferro-magnesite) is
a volcanic variety in which the FeO is essentially replaced by MgO.
G 4' 6-4' 7. Jacobsite is another variety, containing both MgO and
MnO. G 4'75. Many examples of Magnetite are also titaniferous.
These might fairly rank as a distinct species, having the same relation
to Magnetite proper that Ilmenite bears to Haematite.
FRANKLINITE : ZnO, FeO, MnO, Fe2O3, in variable proportions, but
yielding the general formula HO, R2O3. Reg. ; H 6-6-5 ; G 5-5*1 ;
iron-black, streak dark reddish-brown. Usually, more or less mag-
netic. BB, in powder with carb. soda and borax, gives coating of ZnO
on charcoal.
CHROMITE ; normally, FeO, 32, Cr203 68. Reg.; H 5-5; G 4'3 4-6.
Iron-black, streak dark-brownish. Lustre, in most examples, sub-
metallic only.
HEMATITE (Specular Iron Ore): Fe 70, O 30 ( = Fe203). Hemi-
Hex. ; H 5'5-6'5 ;* G 5-0-5-3. Steel-grey, often with variegated
tarnish ; streak cherry-red. Sometimes feebly magnetic. Martite
is a var. in small octahedrons altered from Magnetite.
ILMENITE or MENACANNITE (Titaniferous Iron Ore). Fe?O3, Ti203 in
variable proportions. Henri-Hex.; H 5-5-6; G 4-5-5-3. Iron-black,
dark steel-grey; streak black to brownish-red. Dissolved or attacked
in fine powder by hot hydrochloric acid, the diluted solution by boiling
with tin becoming first colourless and then assuming an amethystine
tint.
ARKANSITE (variety of BROOKITE). Black, sub-metallic lustre.
See TABLE X.
( Yield water in bulb-tube).
TURQITE. Red, blackish-red ; lustre sub-metallic. See TABLES
X., XXIII.
GOETHITE. Red, brown; lustre sub-metallic in some examples.
See TABLES X., XXIII.
* As regards ordinary examples; but the scaly variety, ^'though shewing metallic lustre, soil*
the hands.
MINERAL TABLES : — Vfll.
LIMONITE (Brown Iron Ore). Brown, streak yellowish,
occasionally sub-metallic. See TABLES X., XXIII.
B».— NON-MAGNETIC AFTER IGNITION. ^V*J A
(Strong Mn reaction.* Anhydrom).
PYROLUSITE (Black Manganese Ore): Mn 63'2, O 36'8. Eh.;
H 1-1*5; G 4'7-4-9 ; iron-black, dark steel-grey, streak black; soils
and marks. Ignited, and moistened with HC acid, shews Ba-lines
in spectroscope.
POLIANITE : Identical with Pyrolusite as regards composition and
general crystallization, but with H = 6-7.
BRAUNITE — HAUSMANNITE. Aspect commonly sub-metallic. See
TABLE X.
CREDNERITE. Gives copper reactions. Aspect commonly sub-
metallic. See TABLE X.
(Strong Mn reaction, and yielding aq in bulb-tube).
MANGANITE: MnO2 90-9, H2O 9-10. Rh. ; H 3'5-4; G 4'3-4'5 ;
dark steel-grey ; streak, brown, black.
PSILOMELANE : MnO, BaO, etc., with about 4 or 5 p. c. H2O.
Amorphons (reniform, &c.); H 5-6; G 3'7-4'7. Iron-black, dark
steel-grey ; streak, brownish. Some examples show distinct K-line
in spectroscope. t
(No marked Mn reaction. No ebullition by fusion with borax).
PITCHBLENDE — TANTAUTE — COLUMBITE — YTTROTANTALITE —
SAMARSIUTE — EUXENITE. Lustre sub-metallic, only. See TABLE X.
MUSCOVITE — PHLOGOPITE — and some other MICAS. Lustre pearly-
metallic (pseudo-metallic); foliated or scaly; streak white or greyish.
See TABLES XXV., XXVI.
NOTE ON TABLE VIII.
Minerals of ordinary occurrence belonging to this Table comprise — in addi-
tion to Graphite— the iron ores, Magnetite, Haematite, and Ilmenite ; and the
* Dissolved also, BB, by borax with strong ebullition, caused by liberation of oxygen.
tThis is best seen by igniting the test-substance, and then moistening it with hydrochloric
acid. Green B -lines first appear for a moment, after which the red K-line cornea out very
distinctly and is tolerably permanent. If a piece of deep-blue glass be held between the
gpectroscope and the Bunsen-flame, the yellow Na-line, always present with its accompanying
glare, becomes entirely obliterated, and the red K-line alone remains visible. By ignition and
treatment with HC acid, nearly all manganese oxides of natural occurrence give a momentary
Ba-speetrum,
120 BLOWPIPE PRACTICE.
manganese ores, Pyrolusite and Manganite. The other minerals, mentioned
in the Table, are either rarely met with, or otherwise they present merely a
sub-metallic lustre, and therefore come properly under examination m a
succeeding Table.
Graphite occurs chiefly in foliated or sub-granular masses, more rarely in
hexagonal tables. Its dark colour, flexibility, greasy feel, and property of
marking and soiling, are among its more salient characters. The only mineral
which might be mistaken for it, is the sulphide Molybdenite. The latter is
much lighter in colour, and is at once distinguished by the pale green or
yellowish-green coloration which it imparts to the outer edge of a Bunsen or
other flame.
Magnetite is sufficiently distinguished by its magnetism, and by its black
colour and streak. When crystallized, it is commonly in octahedrons, more
rarely in rhombic dodecahedrons. Franklinite and Chromite are closely
related to it, but possess, as a rule, merely a sub-metallic lustre, and their
streak is more or less brown in colour. Chromite, moreover, gives BB with
borax a chrome-green glass ; Franklinite, with carb. soda, a strong manganese -
reaction.
Haematite presents many varieties, but that which properly belongs to this
Table is the variety known as Specular Iron Ore. This is commonly in dark
steel-grey, laminar, crystalline, or scaly masses, cherry-red in the streak.
The crystals are rhombohedral combinations, often with largely developed
basal plane. R :R = 86°10' ;"B: R = 122°30'. The scaly variety crumbles
under the fingers ; the massive and crystalline varieties scratch glass.
Ilmenite is closely related to Haematite, and closely resembles the latter in
crystallization and general characters, but is usually darker in colour, with
blackish, or indistinctly red, streak. It is best distinguished by the amethystine
colour produced in its hydrochloric-acid solution by boiling with tin. The
student must remember, however, that many examples of magnetite and
haematite are titaniferous to some extent, and with these the reaction would
also be obtained.
Pyrolusite occurs commonly in iron-black or dark steel-grey fibrous masses,
sufficiently soft to soil the hands. It produces chlorine fumes when warmed
with hydrochloric-acid, and the smallest fragment gives with carb. soda, BB,
a strong reaction of manganese in the form of a turquoise-enamel.
Manganite is also of a dark steel-grey or iron -black colour. It occurs com-
monly in groups of prismatic crystals or in coarsely-fibrous masses. The
crystals belong to the Rhombic System, and are frequently twinned. V :.V =
99°40'. Its acid and blowpipe reactions, generally, are the same as in Pyro-
lusite, but it differs from the Utter species by yielding watej: (9-10 per cent,)
in the bulb-tube,
[121]
TABLE IX,
[Lustre sub-metallic. Readily fusible or reducible per se.}
A.— Wholly or partly volatilizable by ignition on charcoal.
A1.— ENTIRELY VOL.
(Hg reaction}.
CINNABAR (HgS). Some dark or lead-grey varieties. Streak red.
G 8-9. Inflammable. See TABLE XI.
(Sb fumes and coating).
KERMESITE (Red Antimony Ore) : Sb2S370, Sb2O330. Dark blueish-
red, with cherry-red streak. Rh. (chiefly acicular and fibrous) ; H 1-5 ;
G 4-5. Melts in candle-flame. See, also, TABLES XI., XV.
A*.— PARTLY VOL., A LARGE SILVER-GLOBULE REMAINING.
(Sb fumes and coating).
MIARGYRITE: Ag 367, Sb 41-5, S 21-8. Clino-Rh. H 2-2-5;
G 5-18-5-26. Iron-black with cherry -red streak.
PYRARGYRITE (Dark Red Silver Ore): Ag 59-8, Sb 22*5, S 177.
Henri-Hex. ; H 2-2-5 ; G 5-75-5-85. Dark lead-grey, reddish-black;
streak cherry-red. See Note, below.
(As fumes).
PROUSTITE (Light Red Silver Ore): Ag 65*46, As 15-15, S 19-39.
Red, blueish-red ; streak bright-red. Lustre, properly, non-metallic.
See TABLE XIV.
RITTINGERITE : Ag (5 7 '1 p. c.) with As, or with Sb, S or Se (?)
Clino-Rh. • H 2-5-3-0 • G 5-6'3 ; iron-black with variegated tarnish ;
reddish or yellow by transmitted light ; streak, orange-yellow.
POLYBASITE : Ag, Cu, As, Sb, S. Iron-black ; red in thin pieces
by transmitted light. Streak, red, black. See TABLES III., IV.
A*.— PARTLY VOL., A CUPREOUS GLOBULE REMAIN^G.
COVELLINE (Indigo Copper Ore): Cu 66*46, S 33-54. Hex. (but
commonly massive, nodular, &c.); H 1-5-2 ; G 4-4*6. Dark coppery-
blue, blackish-blue, with black streak. Inflammable.
CHALKOSINE (Copper Glance): Lustre sub-metallic in occasional
examples, only. Dark iron-grey, usually with greenish coating in
patches. G 5*6. See TABLE III.
122
BLOWPIPE PRACTICE.
A*.— PARTLY OR WHOLLY VOL., WITH PRODUCTION OF LEAD GLOBULE AND
LEAD COATING ON CHARCOAL.
PLATTNERITE: Pb 86-6, 0 134. Iron-black; Hex. (pseudo-
morphous after Pyromorphite ? ); H 3-4 ? ; G 9 -4.
B-— Non-volatile on ignition.
BI.— REDUCIBLE, BB, TO METALLIC COPPER.
CUPRITE (Hed Copper Ore): Cu 88-8, O 11-2. Reg. ; H 3-5-4;
G 5 -7-6. Dark red, sometimes with blueish or lead-grey tinge.
Streak, red. Surface often altered to green carbonate. Tile-ore is
an impure var. mixed with Fe2O3, &c.
TENORITE (Black Copper-oxide). Cu 79-85, O 20-15. Mostly
massive. H 2-3 ; G 5'9-6'5. Blackish steel-grey, iron-black.
B«.— FUSIBLE INTO A MAGNETIC BEAD.
(G 7-7-5. Readily dissolved, BB, by Phosphor-salt. With carb. soda,
strong Mn reaction).
WOLFRAM : FeO, MnO, WO3, in somewhat variable proportions :
the WO3, 76-76-5 p. c. Clino-Rh. ; H 5-5-5; G 7-1-7-55. Dark
brown, brownish black, with brownish streak. See Note, below.
Samarskite — Scarcely fusible. Black. See TABLE X.
(SiO2 reaction with Phosphor-salt. Gelatinizing in hot hydrochloric acid).
ALLANITE — ILVAITE or LIEVRITE — FAYALITE : Black, brownish or
greenish-black. Lustre, properly, non-metallic. See TABLE XXVI.
NOTE ON TABLE IX.
Omitting the silicates, Allanite, Ilvaite, &c., the lustre of which is properly
non-metallic, the commonly occurring minerals of this Table comprise : Cinna-
bar, Kermesite, Pyrargyrite, and Proustite, all of which give a marked sulphur-
reaction with carb. soda on charcoal ; the red, copper-suboxide Cuprite ; and
the tungstate, Wolfram.
Cinnabar presents a sub-metallic lustre in occasional examples only. Most
commonly it has a red colour and non-metallic aspect. Its ready inflammability
and high sp. gr. (8 - 9) serve at once to distinguish it from the other red minerals
of the Table. It forms no deposit on charcoal, but yields readily a grey subli-
mate of metallic mercury if strongly ignited in a closed tube with dry carb.
soda, iron- filings, or other reducing agents. See also, the Note to TABLE XL
MINERAL TABLES I IX. 1 23
Kennesite resembles Cinnabar as regards rapid volatilization, but it forms
on charcoal a dense white coating of Sb203 or Sb205, and its sp. gr. does not
exceed 4 '6. It occurs commonly in tufted groups of acicular crystals, or in
radiated fibrous examples. In a hot solution of caustic potash it is rapidly
converted into an orange-red powder.
Pyrargyrite and Proustite are closely akin by crystallization and chemical
formulae ; but Pyrargyrite is very dark in colour, and it emits, BB, dense
antimonial fumes (commonly accompanied by arsenical odour) ; whilst Proustite
is distinctly red, with commonly an adamantine or non-metallic lustre and
certain degree of translucency, and it is essentially a sulpharsenite. Both
occur commonly massive, or in small (usually indistinct) crystals of the
Hexagonal System, the more frequent forms comprising a combination of
hexagonal prism and rhombohedron, and scalenohedral combinations. Twins
and hemimorphous examples are common. Both species fuse per se when held
against the edge of a candle-flame. The powder becomes immediately black
in a hot solution of caustic potash. Hydrochloric acid precipitates orange-
br-wn Sb2S3, or yellow As'2S5, from the solution. See, also, Notes to TABLES
IVT. and XIV.
Cuprite is separated from the preceding minerals by yielding no sulphur-
reaction before the blowpipe. It occurs frequently in octahedrons and rhombic
dodecahedrons, with green coating of malachite covering the entire surface of
the planes ; more rarely in acicular shapes arising from elongated cubes. It is
also frequently in massive examples. It dissolves in nitric acid with strong
effervescence and production of orange-red nitrous fumes, the Cu*0 being con-
verted into CuO at the expense of some of the oxygen of the acid. The
solution is of course green or blue in colour, and becomes intensely blue on
sufficient addition of ammonia.
Wolfram is readily distinguished by its dark-brown or black colour, and
high sp. gr. (over 7). It occurs massive, and very frequently in somewhat
large crystals of the Clino-Rhombic System : mostly, flattened six-planed
prisms (composed of the forms V and V) terminated by a sharply sloping base
and several polar planes. V : V = 100°37' ; V : V = 140°18' ; B : V = 118°6'.
It fuses into a magnetic globule with crystalline surface. Melted, in powder,
with carb. soda and nitre in a platinum spoon, it forms an alkaline tungstate
soluble in hot water, the bases remaining for the greater part undissolved.
The solution (which at first is green from some dissolved manganate of soda)
when boiled with hydrochloric acid and a piece of tin or zinc, becomes rapidly
colourless, ajad then assumes a deep indigo-blue colour.
[124]
TABLE X.
[Lustre sub-metallic, Infusible ; or fusible on thinnest edges only.]
A —Yielding Sulphur-reaction with carb. soda on charcoal.
(Zn reaction}.
SPHALERITE OR ZINC BLENDE : Zn 67, S 33. Reg.; H 3-5-4 ; G.
3-9-4-2. Brown, black, red, &c.; streak light-brown ; lustre in most
examples, non-metallic, but sub-metallic in many dark varieties.
(Mn reaction).
ALABANDINE: Mn 63-2, S 36-8. Reg.; H. 3-5-4; G 4; black,
brownish, dark steel-grey. Streak greenish, Becomes greyish-green
on ignition. Scarcely fusible, but slags upon surfa.ce and edges in
prolonged heat. No sublimate in closed tube.
HAUERITE : Mn 46-2; S. 53*8. Reg., crystals small, parallel-
planed hemihedrons; H 4; G 3'46. Dark red-brown, brownish
black ; streak brownish or brownish red. In closed tube turns green
and gives sublimate of sulphur.
B.— Magnetic before or after ignition.
B*.— ANHYDROUS.
MAGNETITE (Magnetic Iron Ore) : Fe 72-41, O 27-59, = Fe O. 31,
Fe2O3 69. Reg.; H 5-5-6-5; G 4-9-5-2. Iron black, with black
streak. Strongly magnetic, often showing polarity. Diamagnetite
(of Shepherd) in long rhombic prisms is probably pseudomorphous
after Lievrite (Dana). Pseudomorphs in rhombohedrons, after Spa-
thic iron ore, also occur.
FRANKLINITE : ZnO, MnO, FeO ; Fe203, Mn203, in variable pro-
portions, but giving the common formula RO, R2O3. Reg.; H. 6-6 '5 ;
G 5-0-5-1. Black, with brownish streak. Often strongly magnetic.
CHROMITE (Chromic Iron Ore) : FeO, MgO, CrO ; A12O3, Cr2O»,
Fe2O3 = RO, R2O3. Reg. ; H 5 5 ; G 4-4-4-6. Black, brownish or
greenish black ; streak blackish brown to nearly black. Sometimes
magnetic.
HEMATITE (Red Iron Ore) : Fe 70, O 30 (= Fe2O3). Henri-Hex.,
H (ordinary examples) 5-5-6-0; G 5-5 -3. Steely -red, bluish-red,
with cherry-red streak.
MINERAL TABLES '. — X. 1 25
ILMENITE (Titaniferous Iron Ore): Fe205 Ti208 in variable propor-
tions. Henri-Hex.; H 5'5-6 ; G. 4-5-5 '3. Black, brownish-black ;
streak black to brownish-red. See Note to TABLE VIII.
B«— YIELDING WATER ON IGNITION IN BULB-TUBE,
TURGITE : Fe2O8 94 7, H2O 5-3. H 5-55 ; G 3-55-47 ; black, red-
dish-brown, streak dull red. Hydrohematite is identical or closely
related.
GOSTHITE : Fe'O8 90, H'O 10. Rh.; H 5-5-5 ; G 3'8-4'2. Dark
brown, streak brownish yellow. Lepidochrocite and Stilpnosiderite
are merely varieties, usually containing 3 or 4 p. c. more aq, and
thus passing into ordinary Brown Iron Ore.
LIMONITE or BROWN IRON ORE : FeO3 8-5-6, H2O 14-4. Massive
fibro-botryoidal, &c., often in pseudomorphs after cubical pyrites and
other ferruginous species. H. commonly, 5-5*5, but often lower; G
3 -5-4. Aspect sub-metallic in some varieties only. Brown, brownish
black ; streak brownish-yellow. See, also, TABLE XXIII.
C.— Not Magnetic after ignition.
CV -READILY DISSOLVED (IN POWDER) BY HOT HYDROCHLORIC ACID,
WITH PRODUCTION OF CHLORINE FUMES.*
( B. B. strong Mn reaction).
BRAUNITE : Mn 69-2, O 30-8. A little BaO is often present as in
most manganese ores, and many impure varieties are strongly siliceous.
Tet. ; H. 5-5-6-5 ; G 4-7-4-9. Brownish-black, with similar streak.
HAUSMANNITE : Mn 72, O 28, but BaO, SiO2, <fec., commonly pre-
sent as impurities. Tet. ; H 5-5*5 ; G. 4-7-4-9. Black, brownish
black, with dark-brown streak. Braunite and Hausmannite are
comparatively rare, closely related, species. The crystals are small
Tetragonal octahedrons, often twinned.
PYROLUSITE : MnO1. Black ; soils ; H 2-2-5. Aspect commonly
metallic. Fibrous. See TABLE VIII.
MANGANITE : Mn203 + H2O. Steel-grey, iron-black ; H 3-5-4.
Aspect commonly metallic : See TABLE VIII.
PSILOMELANE : Iron-black, dark steel-grey ; H. 5-6. Gives aq in
bulb- tube. Aspect commonly metallic beneath dark surface tarnish.
See TABLE VIII.
* Recognized unmistakably by the odour. The student should become familiar with this
by warming a little black oxide of manganese with hydrochloric acid.
126 BLOWPIPE PRACTICE.
CHALCOPHANITE : MnO, ZnO, H2O. Hemi-Hex. ; H. 2-5 ; G 3'9.
Blue-black. BB. becomes reddish or copper-coloured.
(Strong Cu reaction}.
CREDNERITE: CuO 43, Mn'2O8 57, but generally impure from
presence of BaO, SiO2, &c. Iron-black, streak black. The hydro-
chloric acid solution is green or bluish, and becomes deep blue on
addition of ammonia, Mn203 gradually precipitating.
C'.— NO CHLORINE FUMES PRODUCED BY TREATMENT WITH HYDROCHLORIC
ACID. Sp. Gr, OVER 2'0.
(Decomposed or attacked by hot sulphuric acid}.*
COLUMBITE : FeO, MnO, Nb2O5, Ta2O6, &c. Rh. ; H 6; G 5-37-6-5.
Iron-black, brownish-black. Streak reddish or greyish-black. Com-
monly yields a little tin by blowpipe reduction.
SAMARSKITE : YO, FeO, CeO, U2O3, Nb2O5, Ta2O, (fee. Rh. ; H
5-6 ; G 5-6-5-8 ; black ; streak red-brown. Diff. fusible into steel-
grey mass. Nohlite (with 4-6 aq) is regarded as an altered variety.
POLYCRASE : YO, CeO, ErO, <fec., with TiO2, Nb2O5, and small per-
centage of water. Rh. ; H 5-6 ; G 5-5-15. Black ; streak brownish.
^ESCHYNITE : CeO, LaO, YO, &c., with TiO2, NbaO5, ThO2, &c.,
and 1 or 2 p. c. aq. Rh. ; H 5-5 '5 ; G 5-5-25 \ black, dark-brown ;
streak brownish.
MENGITE : Fe2O3, ZrO2, TiO2, <fec. Rh. ; H 5-5-5 ; G 5-48. Black;
streak dark-brown.
POLYMIGNITE : YO, CaO, FeO, ZrO2, TiO2, &c. Rh. ; H 6-5. G
4-75-4-85. Black ; streak blackish-brown.
PYROCHLORE : CaO, CeO, Na2O, Fl, ThO2, Nb205, TiO2, &c. Reg. ;
H 5 ; G 4-18-4-37. Blackish or reddish-brown, with light brown
streak. Fusible on edges into a yellowish slag. Generally yields a
little aq in bulb tube.
PEROWSKITE : CaO 4O6, TiO2 59*4. Reg., with cubical cleavage.
H 5-5; G. 4-4-1. Iron-black, yellowish, witn metallic adamantine
lustre.
WARWICKITE: MgO, FeO, B2O8, TiO2. Clino-Rh. ; H. 3-4; G
3-2-3-5. Brown, black, reddish, with dark streak. When moistened
with sulphuric acid, or glycerine, imparts green colour to flame.
PITCHBLENDE — Slightly attacked by sulphuric acid. See below.
*The solution diluted slightly and boiled with addition of hydrochloric acid and a piece of
zinc or tin, assumes a blue, greenish, or violet colour (from presence of Ta, Nb, or Ti).
MINERAL TABLES: — X. 127
( Not attacked, or very slightly attacked, by sulphuric acid).
PITCHBLENDE (Pitch Uran Ore, Nasturan) : TJO, U2O3 (?) with
various impurities. Reg. (?) ; H (usually) 5-6 ; G 6 -5-8. Black,
brownish -black, with black or dark brown streak. Commonly yields
a little aq on ignition. Decomposed in powder, by nitric acid, form-
ing a yellow solution. See TABLE XXIII.
CASSITERITE (Tinstone) : Sn 78-6, O 21'4. Tet. ; H 6-7 ; G 6-5-
7'1. Black, brown, greyish, 'dec. Lustre, as a rule, non-metallic:
See TABLE XXIV. BB., with reducing flux, yields metallic tin.
TANTALITE: FeO, MnO, Ta2O5, Nb2O5, &c. Rh. ; H 6-6-5; G 6-3-8
(usually about 7). Iron-black ; streak dark-brownish. Commonly
gives BB with reducing flux a little tin. TAPIOLITE is apparently a
Tetragonal Tan tali te.
YTTROTANTAUTE : YO, ErO, FeO, CaO, Ta205, WO3, «fec., with 4-6
p. c. aq, but the latter probably a product of alteration. Rh. ; H
5-5-5 ; G (as regards the black sub-metallic varieties) 5-4-5-7; black,
brownish-yellow. Becomes yellow and yields aq in bulb-tube. With
reducing flux gives generally a little tin. HJELMITE is a related
tantalate, containing SnO2, WO3, &c. G 5'82. Black.
FERGUSONITE : YO, ErO, CeO, FeO, <fcc., with Nb2O and Ta205,
and 1-7 p. c. aq. Tet.; H. 5-5-6; G 5-6-5-9. Black, blackish-
brown, with pale brown streak. Tyrite and Bragite are varieties.
EUXENITE : YO, CeO, UO, &c., with Tio2, Nb'05, and 2-3 p. c. aq.
Rh. ; H. 6-5 ; G 4*6-5 ; black, brownish-black; streak, red-brown.
Burns brownish-yellow and yields aq by ignition in bulb-tube.
[NOTE. — The Nio-tantalates and Nio-titaniates of this and the preceding
section are for the greater part very imperfectly known, and all are of rare
occurrence. Several have probably little claim to rank as distinct species.]
RUTILE : Ti 61, O 39. Tet. ; Crystals commonly prismatic, and
often in geniculated twins ; sometimes acicular. H 6-6-5 ; G 4-2-4-3 ;
red, with metallic-adamantine lustre ; more rarely black (Nigrine), or
yellowish ; streak pale brown.
ANATASE or OCTAHEDRITE : Ti 61, O 39. Tet., crystals commonly
pyramidal, of small size. H 5-5-6 ; G 3*8-4 ; dark indigo-blue,
greyish, brownish, with, in general, adamantine lustre.
BROOKITE : Ti 61, O 39. Rh. ; H 5-5-6 ; G 4-4-25. Hair-brown,
reddish, yellowish, black (Arkansite). Comparatively rare.
128 BLOWPIPE PRACTICE.
C«.— NOT ATTACKED BY ACIDS. SPECIFIC GRAVITY UNDER 2.
ANTHRACITE : Carbon, with small amounts of H, O, and N ;
hygroscopic moisture, and inorganic matter or "ash" (1 to over 20
p. c.) being also present in most examples. H 3 (or 2-5-3-25) ; G
1 -2-1 -8 ; black, often iridescent in places ; streak greyish-black.
NOTE ON TABLE X.
Excluding the manganese ores, Pyrolusite and Manganite, the lustre of
which is essentially metallic (see TABLE VIII), the more commonly occurring
minerals of this table comprise the following species : (1) the iron ores, Mag-
netite, Franklinite, Chromite, Haematite, Ilmenite, and Limonite ; (2) The
sulphide Sphalerite or Zinc Blende ; (3) The tin ore, Cassiterite ; (4) The two
forms of Titanic anhydride, Rutile and Anatase ; and (5) the coal variety,
Anthracite.
As regards the iron ores, Magnetite and Franklinite are strongly magnetic
in their natural condition ; the others occasionally are feebly magnetic, but all
attract the magnet strongly after ignition in the R. F. Magnetite is frequently
in large masses, and also in regular octahedrons and rhombic dodacahedrons.
Both colour and streak are black. Thin splinters may be fused at the extreme
point. Franklinite is commonly in small rounded masses imbedded in crystal-
line limestone with red zinc ore, &c., less commonly in cubes and octahedrons,
or in large masses. Its streak is reddish-brown. BB, with carb. soda it
gives Mn and Zn reactions. Some examples are said to be slightly magnetic
only. Chromite is almost always in granular masses of a black colour. Its
sp. gr. is much lower than that of Magnetite and Franklinite ; and it forms
with Borax a fine green glass, by which it is readily distinguished from the
above species. The student must remember, however, that mixtures of these
iron ores often occur.
Haematite is essentially distinguished by its cherry-red streak or powder.
It is commonly in granular, slaty, or fibro-botryoidal masses. Its crystals
generally present a strongly marked metallic lustre. They are mostly rhom-
bohedral combinations with largely developed basal plane (See note to TABLE
VIII.) Ilmenite is a titaniferous haematite, usually of dark colour and dark
streak. Its crystals resemble those of haematite, but the interfacial angles are
slightly different. It is best distinguished by the amethystine colour pro-
duced in its hydrochloric acid solution by boiling with tin or zinc.
Limonite or Brown Iron Ore is distinguished by its ochre-yellow streak, and
by yielding water in the bulb-tube. It is commonly in dark brown masses of
granular or fibrous structure. The surface is often iridescent. Frequently
also it is found in coarse, brown cubes, and other pseudomorphous crystals,
after iron pyrites. Light-brown examples also occur, but these present a silky
or other non-metallic aspect. (See TABLE XXIII).
MINERAL TABLES: — X. 129
Zinc Blende is at once distinguished from other minerals of the Table — the
very rare manganese sulphides excepted — by the sulphur reaction which it
yields with carb. soda. Its powder warmed with hydrochloric acid also emits
the odour of sulphureted hydrogen. Commonly in cleavable masses of a black-
brown, dark -red or yellowish colour, or in groups of crystals (mostly tetrahe-
drons, or combinations of rhombic dodecahedron and tetrahedron) of the
Regular System. A dark ferruginous variety (which becomes magnetic after
ignition) has been named Marmatite ; and a cadmiferous var. (mostly in dark
sub-fibrous masses) is termed Przibramite. (See also the note to TABLE XVI.)
Cassiterite or Tinstone scarcely belongs to the present table, as in most
examples the lustre is essentially non-metallic. Its great weight and hardness,
tetragonal (often twinned) crystallization, and its property of yielding tin
globules by reduction with mixture of carb. soda and borax, are its more
distinctive characters.
Rutile and Anatase (two of the natural representatives of binoxide of Ti-
tanium, the comparatively rare Brookite being a third representative of that
compound), have in most examples a non-metallic (adamantine) lustre, with a
certain degree of translucency. But some examples are opaque. Rutile resem-
bles Cassiterite (and also Zircon, TABLE XXIV.) in its crystallization. The
crystals are commonly composed of two square prisms (forming a pseudo-
8-sided prism) with pyramidal terminations. The prism-planes are striated
vertically in most cases, and the basal plane (as in Zircon) is constantly
wanting. Geniculated twins are common. The colour is generally dark
brownish-red or blood-red, but light-brown and other tints also occur. Ana-
tase occurs in small pyramidal crystals, usually composed of two or several
square octahedrons, the more common one having the angle over a polar edge
= 97°50', and over a middle edge = 136°36'. Prism planes and basal plane
are also occasionally present, and some crystals are tabular from predominance
of the latter. The colour is usually indigo-blue, brown, or greyish-blue. Both
Rutile and Anatase, when fused in fine powder with caustic potash (or with
carb. soda and borax), are attacked or dissolved by hydrochloric acid, the
diluted solution becoming of a deep amethystine tint when boiled with
metallic tin.
Anthracite is at once distinguished from other minerals of the Table by its
low specific sp. gr. j[l'2-l-8). The lustre, moreover, is properly non-metallic.
XXV,
10
[1301
TABLE XI.
[Aspect non-metallic. Readily inflammable : * burning with sulphurous or
alliaceous odour.]
A.— Burning with sulphurous odour.
(Streak^ yellow J.
NATIVE SULPHUR : Eh. ; H 1-5-2-5 ; G 1-9-2-1 ; yellow, brownish,
reddish-yellow. See Note, below.
(Streak, red or brovm).
CINNABAR : Hg 68-2, S 13-8. Hemi-Hex. ; H 2-2-5 ; G- (normally)
8-9, but often lower in dark carbonaceous varieties. Red with red
streak; but sometimes brown from admixture with carbonaceous
matter.
IDRIALINE : A mixture of Cinnabar with earthy matter and C*H>.
Brownish-black ; streak brown or reddish. H 1-1-5 ; G 1-4-1-6.
KERMESITE : (Sb, S, O). Inflammable in some varieties only ;
mostly fibrous or acicular. G 4'5. See TABLES IX, XY. BB, copi-
ous antimonial fumes.
(Streak, black).
COVELLINE : Cu 65-46, S 33-54. Hex. ; H 1-5-2 ; G 4-4-6. Bark
coppery-blue, blackish-blue. BB, copper reaction.
B.— Burning with alliaceous (arsenical) odour.
(Colour, yellow).
ORPIMENT : As 6, S 39, Rh. ; H 1-5-2 ; G 3-4-3-5. Bright yellow,
commonly with metallic-pearly lustre ; streak yellow. In thin pieces,
flexible.
(Colour, red).
REALGAR : As 78, S 30. Clino-Rh. H 1-5-2 ; G 3-5-3-6. Red,
streak orange-yellow.
NOTE ON TABLE XI.
The principal minerals of this Table are N. Sulphur, Orpiment, Realgar, and
Cinnabar. The latter is distinguished more especially by its high sp. gr. and
ita red streak.
* To test this property, a small piece of the mineral may be taken up by the steel forceps and
held for an instant againit the edge of a Bunsen-flame or the flame of a common candle.
MINERAL TABLES I XI. 131
Native sulphur, when crystallized, is commonly, in acute rhombic-octahe-
drons of small size. It occurs generally in indistinct druses, massive or
efflorescent on pyrites, &c. It melts into red-brown drops which become pale
yellow on cooling. From Orpiment, which is equally inflammable, it is dis-
tinguished by its low sp. gr. and by the absence of arsenical odour during
combustion.
Orpiment is occasionally in small prismatic crystals, but occurs generally in
foliated or other examples. It dissolves entirely in caustic potash, and is re-
precipitated from the solution by hydrochloric acid.
Realgar is distinguished from Cinnabar by its orange-yellow streak, as well
as by its lower sp. gr. , and the arsenical odour evolved on combustion. Its
crystals are small Clino-Rhombic prisms with largely developed basal plane,
but are generally in druses, or otherwise indistinct. Most commonly it occurs
in granular or other masses. In caustic potash it leaves a brown residuum of
sub-sulphide. Otherwise like Orpiment.
Cinnabar is the essential ore of mercury. Under normal conditions it pre-
sents a scarlet red colour (whence its old name of Native Vermilion) and un-
changed streak, but the surface is usually brownish, and many examples are
dark-brown from intermixed earthy or bituminous matter (Liver Ore, &c.)
The crystals are combinations of rhombohedrons and hexagonal prism, the
triangular basal plane being especially apparent. Tetartohedral forms have
been recognized, but in general the crystals are small, and more or less in-
distinct. Cinnabar occurs more commonly in granular masses, and occasionally
in thin coatings or incrustations. Metallic mercury is easily sublimed from it
by ignition with dry carb. soda, iron filings or other reducing agents, in a small
flask or test-tube. Scarcely attacked by caustic potash, or by nitric or hydro-
chloric acid. Soluble in aqua regia.
[132]
TABLE XII.
[Aspect non-metallic. Inflammable in candle flame, burning with bituminous
or aromatic odour.]
A —Coaly, ligneous, or pitch-like aspect. Burning with
bituminous odour.
BITUMINOUS COAL : C 74-96, H 0-5-5-5, O 3-20. Black, often iri-
descent ; streak, black. H 2-2-5 ; G 1-2-5.
LIGNITE or BROWN COAL: C 55-80; H 3-6 ; 0 17-27. Dark-
brown or black (jet) with brown streak. H 2-2-5 ; G 1-2-1.4. Mas-
sive, ligniform, sometimes foliated (Paper Coal), and earthy. Imparts
a brown colour to caustic potash. "Torbarnite" is sometimes referred
to this variety, but it is properly a mere bituminous shale.
BITUMEN or ASPHALT : C, H, O. Black, greenish-black. H 0-5-
2-0; G 1-0-1*2. Semi-fluid or pasty in ordinary examples, also in
stalactitic and other more or less brittle masses with conchoidal
fracture. Passes into Petroleum.
ALBERTITE : C, H, N, O. Black, highly lustrous, brittle. H 2-
2-5 ; G 1-1 -1. Scarcely attacked by alcohol, but partially dissolved
by oil of turpentine. STELLARITE .and GRAHAMITE are related sub-
stances.
ELATERITE (Elastic Bitumen) : C, H, O. Dark-brown or black.
Soft and flexible, resembling caoutchouc. Passes into ordinary bitu-
men. G 0-8-1-2. DOPPLERITE is a closely related substance.
B-— Resinous (or when dark coloured somewhat coaly) in
aspect, but burning with aromatic (non-bituminous) odour.
PIAUZITE : dark-brown, with yellowish -brown streak. H 1-5-2;
G 1-18-1-22. Soluble in ether and in caustic potash. Pyroretine is
apparently related.
.AMBER (Succinite, Bernstein) C, H, O (= C 79, H 10-5, O 10-5?).
Yellow, brownish, reddish, greyish- white. Mostly in nodular masses.
H 2-2-5 ; G 1-0-1-1. Electric by friction.
BETINITE, KRANTZITE, IXOLITE, SIEGBURGITE, PYROPISSITE, and
other obscurely known amber-like substances, belong also to this
group.
MINERAL TABLES: — xn. 133
C.— Wax-like in aspect.
OZOKERITE (Keftgil): Essentially C 85-7, H 14-3 (2-3 per cent. O
present in some examples). Green, brownish (by transmitted light,
yellowish or red). Very soft, pasty ; G 0'95. Emits per se an aro-
matic odour. Easily sol. in oil of turpentine. Scarcely or slowly sol.
in ether and alcohol.
PARAFFINS — URPETHITE — HATCHETTINE — GEOCERITE— GEOMY-
GERITE — EUOSMITE : Greyish- white to brownish yellow, soft wax-like
substances, more or less readily soluble in ether.
HARTITE.- — A white or brownish crystalline, wax-like substance,
soluble in ether. See under D, below.
D.— Crystalline in aspect-
FICHTELITE : C 87-13, H 12-87. In white, pearly, crystalline
laminae, soluble in ether. After fusion, becomes again crystalline
on cooling. TEKORETINE (Clino-Rhombic) is identical.
SCHEERERITE (Konleinite) : C and H. In white acicular or lamel-
lar crystals (Clino-Rhoinbic). G 1-1-2. Dissolves readily in ether,
but rapidly separates again.
HARTITE : C and H. In soft paraffine-like, white or brownish
crystalline lamellae, or small (anorthic) crystals. H 1 -0-1 -5 ; G
slightly over I'O. Largely soluble in ether, BOMBICCITE is a related
crystalline (anorthic) compound, but is said to contain nearly 15 per
cent. 0, Easily soluble in ether and in alcohol.
NOTE ON TABLE XII.
The substances included in this Table are essentially hydro-carbon com-
pounds, probably in great part (or wholly, according to the common view),
of organic origin. The absolutely organic nature of asphalt and other bitu-
minous substances, remains, however, yet to be proved. Many other com-
pounds enumerated by chemists might have been referred to in the Table ; but
the composition of these hydro-carbons appears to be more or less variable,
and their physical characters, in most instances, cannot be very rigorously
defined. The more common representatives of the Table comprise — Bitumin-
ous Coal, Brown Coal, and Amber, The latter occurs mostly in nodular or
irregular masses of a light or deep yellow colour, but is sometimes greyish- white
or brownish, and frequently clouded. Some examples are quite transparent,
others only translucent, and many are quite opaque. Leaves and insects are
134 BLOWPIPE PRACTICE.
frequently enclosed in these nodules, and thus amber is usually regarded as a
coniferous gum or resin of Cainozoic age. Fraudulent imitations of insect-
holding amber are often imposed, however, on the unwary. Like other resin-
ous bodies, amber is rendered strongly electrical by friction.
Bituminous coals generally leave, by ignition in closed vessels, a semi -fused
agglutinated coke. These are commonly known as "caking coals." In
brown coals, proper, the coke remains unf used. In all kinds of coal, sulphur
(from pyrites, and occasionally from gypsum,) is present more or less ; and all
coals contain a certain amount of intermixed earthy matter or " ash." This
latter may vary from 2 or 3 to 10 or 15 per cent , but many coals pass into
coal shales, when the amount of earthy matter (essentially a silicate of alu-
mina) may exceed 50 per cent. All coals, moreover, contain hygroscopic mois-
ture, varying (according to conditions of exposure, &c.,) from about 3 or 4, to
over 10 or 12 per cent., or higher in many brown coals. See Appendix to
" Blow-pipe Practice," page 76, On the Examination of Coals by the Blowpipe.
[135]
TABLE XIII.
[Non-metallic aspect . Readily sol., BB., in phosphor-salt. Effervescing in
diluted hydrochloric acid, (N, B. — The acid in some cases must be
gently heated.)]
A,— Yielding metallic globules, per se, or with carb. soda on
charcoal.
A*— ANHYDROUS SPECIES. NO WATER, OR PAINT TRACES ONLY, IN BULB-
TUBE.
(No reaction of 8 or Cl).
CERUSSITE : PbO, 83-52, CO2 16-48 = Pb 77'6. Rh. ; H 3-3-5 ;
G (normally) 6 -4-6-6, but lower in impure earthy varieties. Colour-
less, or grey, nearly black, yellowish, &c.; streak white. IGLEASITE
is a zinc-holding variety.
PLUMBO-CALCITE : = Plumbiferous var. of Calcite or Calc Spar,
TARNOWITZITE = Plumbiferous var. of Arragonite. G about 2-8.
Both give a lead sublimate on charcoal, but metallic globules are not
readily obtained.
(8 reaction).
LEADHILLITE : PbO, CO2 72-56, PbO, SO3 27-44 = Pb 75. Eh. ;
H 2-5-3; G 6'2-6'6. Yellowish-white, grey, brownish, &c., streak
white. SUSANNITE is a supposed rhombohedral variety (G 6-55).
MAXITE is probably an altered var., containing a small percentage of
water.
CALEDONITE : PbO, CuO, SO3 (CO2 by alteration or admixture).
Light-green. See Table XYI.)
(Cl reaction).
PHOSGENITE (Kerasine) : PbO, CO2 49, PbCP 51, = Pb 73-8.
Tet. ; H 2-5-3; G 6-6*3. Yellowish-white, grey, yellow, green;
streak white.
A*— YIELDING WATER ON IGNITION.
( Cu reaction).
MALACHITE: CuO 71-95, CO2 19-90, IPO 8-15. Clino-Rh., but
rarely crystallized. H 1-0-4; G 3-7-4. Green, often zoned in dif-
ferent shades ; streak light-green. Some varieties are calcareous.
ATLASITE is a variety containing copper chloride.
AZUKITE (Chessylite) : CuO 69'2, CO2 25-6, HaO 5-2. Clino-Rh.;
H 1-4; G 3*7-3-8. Blue, paler in the streak.
136 BLOWPIPE PRACTICE.
See also TIROLITE, Table XIV, many examples of which contain
intimately intermixed carbonate of lime. Green or blue radiated
masses, or earthy. BB, strong arsenical odour.
(Cu and Zn reactions).
AURICHALCITE : CuO 28, ZnO 46, CO216, H20 10 (?). Acicular
or fibrous. H 2 ; G about 3*3. Green or bluish j streak paler.
BURATITE is a calcareous variety.
( Bi reaction).
BISMUTITE : BiO, CO, H'0. H 4-4-5 (?) G 6-8-6-9 (?). Yellow,
grey, green ; streak paler. A doubtful species, more or less variable
in characters and composition.
B.— No metallic globules obtained by fusion with carb soda
on charcoal.
BI— ANHYDROUS SPECIES. NO WATER, OR TRACES ONLY, IN BULB TUBE.
(NoTE: — The presence of Ca, Ba, Sr, singly or together, in carbonates of
this group, is very readily ascertained by a small, direct vision spectroscope.
See Outline of Blowpipe Practice, pp. 55, 57.
f Magnetic after ignition.
SIDERITE (Spathic Iron Ore) : FeO 62, CO238, = Fe 48-2 ; part of
the FeO, however, often replaced by MgO, MnO, CaO. Herui-fiex. ;
H 3 5-4 -5 ; G 3*7-4-1 ; yellowish-grey, yellow, brown, olive-green,
&c., streak paler. SPHEROSIDERITE is a fibrous-spherical variety
from trap rocks ; CLAY-!RONSTONE, BLACK BAND, &c., are impure
argillaceous or bituminous varieties from coal strata. SIDEROPLE-
SITE, MESITINE and PISTOMESITE (G 3-3-3-6) are crystalline magne-
sian vars. ; and OLIGON SPAR, a variety containing 25*5 p. c. of MnO
CO2. In the typical rhombohedron, R : R = 107°, whilst in the Mg
and Mn examples it varies from 107°3' to about 107°18'. Crystals,
however, commonly present curved planes.
ANKERITE : (CaO, MgO, MnO, FeO) CO2. Hemi-Hex., with RR
about 106° 12'. White, yellowish, brownish ; streak, in un weathered
examples, white. H 3-4; G 2-9-3-3. Merges into Siderite, Calcite,
and Dolomite.
See also dark-coloured varieties of MAGNESITE and DOLOMITE.
ft Not magnetic on ignition , and no marked alkaline reaction.
MINERAL TABLES I — XIII. 137
(Strong reaction of Mn).
RHODOCHROSITE (DIALLOGITE, MANGANESE SPAR) : MnO 61-74,
CO2 38-26, but MnO often in part replaced by CaO and MgO. Hemi-
Hex, with R : R (normally) 106°5'. H 3'5-4'5 ; G- 3-3-3-6. Rose-
red, pink-brownish when weathered ; streak very pale red, reddish-
white. Blackens on ignition. RCEPPERITE is a calcareo-magnesian
variety.
(Co reaction).
SPH^ROCOBALTITE (Cobalt spar) : CoO 63, CO2 37. H 4 ; G 4-0-
4*1. In spherical concretions, black externally, red within. A
doubtful species.
(Zn reaction).
SMITHSONITE (Calamine, Zinc Spar) : ZnO 64-8, Co235-2. Hemi-
Hex., with R : R = 107°40'. H 5; G 4-4-5. Colourless, pale-
greyish, greenish, brownish ; streak, white. Many varieties contain
FeO and MriO. HERRERITE is a cupreous variety.
f |f Alkaline reaction, after strong ignition.
(Ba reaction : flame coloured pale-green).
WITHERITE : BaO 77-67, CO2 22-33. Rh., with pseudo-hexagonal
aspect. H 3-3-5 ; G 4"2-4*4. Colourless, pale-grey, yellowish ;
streak white. BB, entirely soluble in carb. soda.
ALSTONITE (Bromlite) : BaO, CO2 66-33 + CaO, CO2 33-67. Rh.;
H4-4-5; G 3-6-3-8. Colourless, greyish ; streak white. BB, only
in part sol. in carb. soda.
BARYTO-CALCITE : Composition and general characters as in ALSTO-
NITE ; but crystallization Clino-Rhombie, with V : V 84° 5 2'.
(Sr reaction: crimson flame-coloration).
STRONTIANITE : SrO 70-27, CO2 29-73. Rh. (V : V = 117Q19') ;
H 3*5; G 3-6-3-8. Colourless, greenish, yellowish, &c.; streak
white. Some varieties are more or less calcareous ; others (Strom-
nite) contain baryta,
(Ga reaction : flame, after prolonged ignition of test- substance, coloured red).
CALC SPAR or CALCITE : CaO 56, CO244. Hemi-Hex, with rhom-
bohedral cleavage (R : R 105°5' ; or varying from about 105 to 105°
18', part of the CaO being commonly replaced by MgO, FeO, &c).
H (normally) 3, but often lower; G 2*6-2 -8. Colourless or variously
tinted ; streak white. See Note below.
138 BLOWPIPE PRACTICE.
DOLOMITE (Bitter Spar) : CaO, CO2 54-35, MgO, C0« 45-65, but
often more or less ferruginous, &c. Hemi-Hex (R : R 106*15' 106°
20'); H 3-5-4; G 2-8-3-0. Colourless, yellowish, brownish, &c. The
varieties containing FeO are commonly called Brown Spar. Through
these there is a complete transition into Aiikerite and Siderite.
GURHOFIAN and KONITE are impure silicious varieties, with H =
4-5-5-5.
ARAGONITE: CaO 56; CO2 44. Rh. (V : V 116*10'); H 3-5-4 ;
G 2-7-3-0, normally 2 -9 4. Colourless, light-yellow, brown-violet,
reddish, greenish ; streak white. Commonly falls into powder on
ignition. Some examples contain a small percentage of strontia.
Flos Ferri is a coralloidal var., accompanying iron ore at certain
localities. TARNOVITZITE is a highly plumbiferous variety.
(Mg reaction : No flame coloration, if pure ; reddened by ignition with cobalt-
solution).
MAGNESITE : MgO 47'62, CO2 52-38, but part of MgO commonly
replaced by FeO, CaO, &c. Hemi-Hex. (R : R 107°16'— 107*29').
H 3-4-5, or lower; G 2-8-3-1. Colourless, snow-white, yellow,
greyish, <fcc. ; streak white. GIOBERTITE is merely crystallized
Magnesite.
B*— HYDROUS SPECIES, YIELDING WATER BY IGNITION IN CLOSED TUBE.
f Soluble or partly sol. in water.
NATRON: Na2O 22, CO2 15, H2O 63. Clino-Rh. (V: V = 79*41'),
but chiefly earthy and efflorescent. H 1-1*5 ; G 1-4-1-5. Normally
colourless.
THERMONATRITE : Na2O 50, CO2 35-5, H2O 14-5. Rhombic,
mostly in rectan. tables ; H 1-5; G 1-5-1-6. Normally colourless.
TRONA: Na2O 38, CO2 40, H'O 22. Clino-Rh.; H 2-3; G 2-1-2-2.
Normally colourless. Commonly mixed with NaCl.
GAYLUSSITE : Na2O CO2 35-50 ; CaO, CO2 34-08, H2O 30-42. Clino-
Rh (V : V 68-51'). H 2-5 ; G 19-4 ; colourless. Slowly, and only
in part, soluble in water.
ft Insoluble in water. Giving BB with borax an uncoloured or very
lightly-tinted glass.
GAYLUSSITE : Partly sol. See above.
HYDROMAGNESITE : MgO 44, CO2 36-2, H2O 19-8. Clino-Rh., or
Rh. (V : V 87* — 88°), but commonly massive or earthy; white;
MINERAL TABLES: — xm. 139
H 1-3-5 ; G 2-1 4-2-18. Some of the earthy varieties give only 4 or
5 p. c. water on ignition. BAUDISSERITE is an impure silicious var.
LANCASTERITE, according to Smith and Brush, is a mixture of Hydro-
rnagnesite and Brucite. Hydrodolomite, in white or yellowish
spherical masses from Vesuvius, is a compound of Hydromagnesite
with Calcite or Dolomite.
HYDROZINKITE (Zink Bloom): ZnO 75-24, CO 13-62, HX) 11-14.
In white or yellowish earthy or oolitic masses, or efflorescent on zinc
ores. G 3-25.
DAWSONITE : A compound (or mixture produced by alteration 1) of
APO, CaO, Na'O, CO2 and H2O. In colourless, thin-bladed aggre-
gations or coatings on compact trachyte, Montreal. H 3 ; G 2 -4.
HOVITE, in white earthy crusts, is apparently related in composition.
TENGBRITE : YO, CO2, H2O. In white or yellowish earthy crusts
on certain examples of Gadolinite.
LANTHANITE : LaO 52-6, CO 21-3, IPO 26-1. Rh. (Y : Y 92°50'
— 94°), generally tabular. H 2'5-3'0; G 2*67 ; greyish or yellowish-
white, pale red. BB, with borax, a pink or pale violet bead, appa-
rently from the presence of Didymium.
tjt Insoluble in water. Giving, with borax, a strongly-coloured glass.
WISERITE: MnO, CO2, H2O. In yellowish or pale-red fibrous
coatings on certain examples of Hausmannite and other manganese
ores.
ZARATITE (Texasite) : NiO, CO2, H2O. In thin emerald-green
coatings on nickle ores. Also on examples of Chromic Iron Ore from
Texas, Penn.
REMINGTONITE : CoO, CO2, H2O. In pinkish, or greyish-blue
coatings on cobalt ores. ^
LINDAKERITE (Calc-Uran Carbonate). In coatings and crusts on
Pitchblende. Yellowish-green. Contains (according to Lindaker)
UO 37-03, CaO 15-55, CO2 24-18, H'O 23-24. YOGLITE is a cupre-
ous variety. LIEBIGITE is also a closely related compound, but with
45 p. c. aq. All occur in connection with pitchblende.
NOTE ON TABLE XIII.
The more important minerals of this Table comprise : (1) Calcite, Dolo-
mite, Magnesite, Siderite, Rhodochrosite, and Smithsonite, of the group of
140 BLOWPIPE PRACTICE.
Rhombohedral Carbonates; (2) Aragonite, Witherite, Strontianite, and Cerus-
site, of the group of Prismatic Carbonates ; and (3), the Cupreous Carbonates,
Malachite and Azurite.
Calcite, in its crystalization, chiefly affects three series of forms : (i) Rhom-
bohedrons, acute and obtuse ; (ii) Scalenohedrons ; and (iii) Hexagonal Prisms,
the latter commonly terminated by the three planes of a rhombohedron, pen-
tagonal in shape in some cases, rhombohedral in others. The basal plane, when
present, is usually rough or dull. Some of the more common fhombohedrons
comprise : - £ R (polar angle 135°) ; - 2 R (polar angle 79°) ; and 4 R (p. a. 66e).
The most common scalenohedron has the following interfacial angles : over
long polar edge 159°24' ; over shorter polar edge 138°5' ; over middle edge
64°54'. All crystals and lamellar examples cleave readily into a rhombohedron
of about 105°5' and 74C>55/, but these angles vary to within about 30' in con-
sequence of isomorphous replacements, a small portion of the lime carbonate
being almost constantly replaced by carbonate of MgO, FeO, or MnO. Trans-
parent examples show strong double refraction in the direction of the longer
diagonal of a rhombohedral face. Pseudomorphs, after Orthoclase, Fluor Spar,
Barytine, Celestine, Gypsum, Gaylussite, &c., are not uncommon. Calcite
occurs likewise in rock-masses, forming crystalline limestone (marble), ordinary
limestone, oolitic limestone, chalk, &c., and in various stalactitic, tufaceous,
and other conditions. Calcite, after simple ignition (without the aid of hydro-
chloric acid, although it is always advisable to add a drop of this), shews the
red and green calcium lines in the spectroscope very distinctly.
Dolomite much resembles calcite in its general characters and rhombohedral
crystallization, but it dissolves, as a rule, in cold acids with comparatively
feeble effervescence. Both hardness and sp. gr. are also slightly higher. The
most certain method of distinction is the determination of magnesia in the
hydrochloric acid solution. For this purpose the diluted solution is first
boiled with a drop or two of nitric acid, and ammonia is then added in slight
excess. This will cause a slight floceulent precipitate if iron be present.
Oxalate of ammonia is then added to precipitate the lime ; this is filtered off ;
the filtrate tested with another drop of oxalate of ammonia to make sure that
all the lime has been thrown down, and the magnesia is precipitated by some
dissolved phosphor- salt. It can be collected, if necessary, and ignited with
nitrate of cobalt for the production of the characteristic flesh-red tinge.
Many so-called limestones when examined in this manner are found to be
" dolomitic." Ferruginous varieties of Dolomite pass into Ankerite.
Magnesite is comparatively rare in crystals, but occurs commonly in more
or less compact or granular masses, beds, or layers of a white, pale-grey or
yellowish colour. The small rhombohedrons show over a polar edge the angle
107° 16' to 107°29'. The powder by ignition with a drop of cobalt solution, is
distinctly reddened. .The absence of lime can be proved by the spectroscope ;
and the presence of magnesia by the cobalt test or by precipitation, as
explained under Dolomite.
Siderite or Spathic Iron Ore occurs under various conditions : crystallized
in metallic veins, &c. ; fibro-botryoidal ; in spherical concretions in basaltic
MINERAL TABLES : — XIII. 141
rocks ; pisolitic in Jurassic and other strata ; massive ; and lithoidal. The
crystals are usually small rhombohedrons of a yellow colour (with R : R 107^
but frequently with curved faces), also acute rhombohedrons and scalenohe-
drons. The spheroidal basaltic variety is usually dark-green or yellowish-
brown, with radio-fibrous structure. The pisolitic variety, dark-brown or grey,
and opaque ; and the lithoidal and massive examples dark-grey, brown or
black, and also opaque. These latter kinds commonly occur in oval or nodular
masses in coal strata, or in layers mixed with coaly matter. Under the name
of Clay Iron-Stone, Black Band, &c., they furnish a large part of the iron of
commerce, but are always very impure from admixture with clay, silica, &c.
They are also more or less altered, as a rule, into brown iron ore. The nodules,
when split open, are usually found to contain the impression of a fern-frond or
other organic body.
Rhodochrosite or Manganese carbonate is of less frequent occurrence than
the preceding carbonates. Its crystals are mostly small rhombohedrons (with
usually curved faces) sometimes shewing a triangular basal plane (R : R 106°
51' — 107°) ; but it occurs commonly in botryoidal, granular or lamellar masses,
of a pink or rose-red colour, with dark-brown altered patches. As in Magnesite
and Siderite, it effervesces feebly unless the acid be heated. Its red colour and
intense manganese reaction, BB, with carb. soda, generally serve to distin-
guish it at once from other carbonates ; but many examples of Magnesite,
Siderite, &c., give a more or less strongly -marked manganese reaction. No
very definite lines of demarcation, in fact, can be drawn between the rhombo-
hedral carbonates generally.
Smithsonite, or zinc carbonate, occurs mostly in aggregations of minute
rhombohedrons, or in botryoidal or incrusting examples of a white, brownish,
grey, yellowish, or green colour. It is usually more or less vitreous and
transparent ; but is sometimes in opaque, grey or brown, earthy or porous
masses. The streak is white, and the hardness just sufficient to scratch
glass ; or sufficient, at least, to scratch fluor spar very strongly. In powder,
with a mixture of carb. soda and borax, it yields on charcoal a sublimate of
ZnO, — bright-yellow and phosphorescent, hot ; white, cold ; and light-green
after ignition with cobalt solution.
Aragonite — the typical representative of the group of Prismatic carbonates —
is identical in composition with the rhombohedral calcite. It occurs frequently
crystallized, and in fibrous, coralloidal, and other masses. The crystals
belong to the Rhombic System, and are generally six-sided prisms, composed
of four V planes with the two side planes of a brachy-prism V, terminated by
a brachy-dome P, and by the planes of a rhombic octahedron P ; but the latter
form is often absent. V : V = 116°10' j V : V = 121°55' ; V : P = 125°47'.
Twins and compound crystals are very common. Some of the latter, com-
posed of three or more individual crystals, are strikingly pseudo-hexagonal in
character, presenting the appearance of a simple six-sided prism with large
base. The colour is white, yellow, brownish-violet, &c. All examples dis-
142 BLOWPIPE PRACTICE.
solve with strong effervescence in cold acids, and show, after moderate ignition,
the characteristic red and green calcium lines in the spectroscope.
Witherite, carbonate of baryta, also presents in its crystallization a pseudo-
hexagonal aspect. The crystals are, very generally, six-sided pyramids, but
are regarded as compound crystals, made up of interpenetrating rhombic-
octahedrons. Columnar, botryoidal, and massive examples are however its
principal forms of occurrence. Its high sp. gr. (over 4'0), and the green colour
which it imparts to the flame border, sufficiently distinguish it from other
carbonates.
Strontianite, like Witherite, is entirely dissolved by fusion with carb. soda ;
and its sp. gr. is comparatively high (3'6-3'8). It is readily distinguished,
however, by the intense crimson coloration which it communicates to the
flame-border, and by the characteristic blue, orange, and red lines, of its
spectrum. Its crystallization is identical with that of Arragonite, and is
characterized by pseudo-hexagonal combinations and twin forms ( V : V —
117°19' ; V : V = 12i°20'30" ; V: 2P = 145°22'). Strontianite occurs more
commonly, however, in columnar, fibrous, granular and other examples.
Cerussite, or lead carbonate, is also identical in crystallization with Ara-
gonite, and is particularly characterized by its stellate and cruciform groups
(V: V = 117°14', V: 2P = 145°20'). The lustre is strikingly adamantine.
This character, with the high sp. gr. (6 '5) of the species, its remarkable
fragility, and its blowpipe reactions, sufficiently distinguish it.
The copper carbonates, Malachite and Azurite, yield water on ignition, and
are otherwise distinguished by their deep green and blue colours, and their
copper reactions. Malachite (although often, as a product of alteration, entirely
coating octahedrons and dodecahedrons of red copper ore, Cu2O) is very rarely
crystallized, but occurs commonly in botryoidal, fibrous and massive examples,
and as an earthy coating on copper ores generally. Azurite, the blue carbonate,
is frequently in groups of small clino-rhombic crystals, more or less indistinct
in form. It occurs also in columnar and other masses, and in earthy coatings
on copper ores.
[148]
TABLE XIV.
[Aspect non-metallic. BB, on charcoal, arsenical fumes or odour.]
A —Entirely volatilizable, or leaving only a minute residuum.
(Streak white).
ARSENOLITE (Arsenious acid): As 75-8, O 24-2. Reg.; H 1-2;
G 3'7 ; in white, crystalline or acicular groups and coatings, and in
earthy crusts. CLAUDETITE (Dana) is a rhombic species, in small
sub-pearly laminae. G 3 -85.
(Streak black).
NATIVE ARSENIC, weathered examples. In dull, black, earthy
masses, often coating the metallic-grey or tin-white unaltered metal.
See TABLE I.
B —Yielding, BB, metallic globules on charcoal, (A mixture
of carb- soda and borax assists the reaction).
(BB, a silver globule).
PROUSTITE (Light-red Silver Ore). Ag 65 '46, As 15-15, S 19-39.
Henri-Hex. ; H 2-2-5 ; G 5*4-5-6 ; red, more or less translucent, with
adamantine lustre ; streak, red.
XANTHOCONE : Ag 64-08, As 14-83, S 21-09. Hemi-Hex., mostly
tabular. H 2-2-5 ; G 5-0-5-2. Orange or brownish-yellow, trans-
lucent or transparent, with adamantine lustre. Streak orange-yellow.
RITTINGERITE : Normally AgAs (with 57*7 Ag), but S commonly
present. Clino-Rh. ; H 2-5-3 ; G 5-6-3. Iron-black, red by trans-
mitted light ; streak orange-yellow. Lustre in general strongly sub-
metallic. See TABLE IX.
POLYBASITE, arsenical varieties. Ag (64-74), Sb, As, S ; !Rh. ;
H 2'5; G 6-0-6-2. Iron-black, red in thin pieces by transmitted
light; streak, commonly dark-red. Lustre, usually metallic. See
TABLE IV.
All the above arsenical silver ores fuse per ne in the flame of a candle, with-
out the aid of the blowpipe. Rittingerite and Polybasite are still imperfectly
known.
(Cu reaction).
OLIVENITE: CuO 56-15, As'O6 40-66, H'O 3-19. Kb, (V:T
92°30') ; H 3 ; G 4-3-4-6 ; dark-green, brownish \ streak, paler.
144 BLOWPIPE PRACTICE.
EUCHROITE: CuO 47-15, As205 34-15, H20 18-70. Rh. (V : V
117°20'); H 3-4; G 3-3-3-5; emerald-green, leek-green; streak,
paler. CHLOROTILE is closely related.
ERINITE : CuO 60, As2O5 34-6, H2O 5'4. Mostly in concentric-
lamellar examples ; H 4-5; G4-0; emerald-green; streak, paler.
TIROLITE (Kupferschaum) : CuO 50-32, As206 29-15, H2O 20-53.
Mostly in radio-fibrous mammillary examples. H 1-2 ; G 3-1. Green
or greenish-blue ; streak, paler. Most examples are intimately mixed
with CaO, CO2. The presence of Ca, readily shewn by spectroscope.
CLINOCLASE (Abichite, Aphanese, Strahlerz) : CuO 62-65, As205
30-25, H2O 7-10. Clino-Rh.; H 2«5-3; G 4-2-4-4; dark-green,
bluish-green, blackish externally ; streak, paler.
LIROKONITE (Linsenerz) : CuO, As2O5, A12O3, H20 (25 per cent.).
Clino-Rh.; H2-2'5; G 2 -8-2 -95; light-blue, sometimes green; streak,
paler.
CHALCOPHYLLITE (Copper Mica) : CuO, As205, A12O8, H20 (23-32
per cent.). Hemi-Hex., tabular, micaceous. H 2 ; G 2-5 ; bright
emerald-green ; streak, paler.
ZEUNERITE: CuO 7'71, TPO» 55-95, H20 14. Tet., isomorphous
•with Chalcolite or Torbernite. H 3*5 ; G 5*76; orange or wax-yellow,
with adamantine lustre ; streak, paler.
ADAMITE : Cupreous varieties. Green. G 4*35 ; zinc sublimate
with carb. soda on charcoal. See below.
(Pb reaction).
MIMETESITE : PbO, As2O5 90-7 ; PbCl2 9-3. Hex. (crystals often
sub-spherical). H 3-5-4 ; G 7-7*3 ; yellow, green, greyish, colourless,
with resino-adamantine lustre. KAMPYLITE and HEDYPHANE (G 5-5)
are more or less calcareous and also phosphatic varieties. Some of
the orange-yellow examples contain lead chromate. All give Cl
reaction with phosphor-salt and CuO.
AR^JOXENE: PbO, ZnO, V206, As2O5. Radio-fibrous; H 3;
G 5 -8 ; brownish-red ; streak, yellow.
CARMINITE (Karminspath) : PbO 23-62, Fe208 29-14, As206 47'24.
Acicular, mammillated. H 2-5 ; G 4'1 ; red; streak, reddish-yellow.
BEUDANTITE : PbO, Fe203, P2O5, As2O5, SO3, H2O. Hemi-Hex. (?)
H 3'5 ; G 4:0. Olive-green; streak, yellowish. A doubtful species.
MINERAL TABLES : — Xltf. 1 45
(.Bi reaction).
RHAOITE : Bi2O* 79 5, As2O5 15-6, H2O 4-9, Mostly botryoidal or
in small spherical examples. H 45-5 ; G- 6*82 j light-green ; streak,
very pale green or white. In bulb-tube crumbles into yellow powder.
Accompanies uran ores at Schneeberg.
WALPURGINITB : Bi2O8, IPO3, As2O5, H20 (4-5). Clino-Rh.?;
orange or wax yellow, with resino-adamantine lustre ; streak, paler ;
H3-5; G 5-76. Accompanies uran ores at Schneeberg. ATELESITE
is apparently related.
C.— No metallic globules, BB, on charcoal.
(Zn reaction. Characteristic sublimate with carb. soda on charcoal).
ADAMITE : ZnO 56-6, As205 40-2, H'O 3-2, but some green examples
contain CuO, and red examples, CoO. Rh. ; H 3-5 ; G 4-3-4-35.
Normally, yellow ; but often violet, red, or green ; streak, paler.
KOTTIGITE : Zinc-holding var. of ERYTHRINE. See below.
(Co reaction).
ERYTHRINE (Cobalt Bloom) : CoO 37-56, AsW 38-40, H20 24-04.
Clino-Rh. ; H 2-5; G 2-9-3-0. Red, purplish-red; streak, paler.
Some earthy varieties contain intermixed arsenolite. KOTTIGITE is
a zinc-holding var.
ROSELITE : CaO, MgO, CoO, As2O5, IPO (8-20). Rh. or Cl.-Rh.
H 3-3-5 ; G 3-46 ; deep rose-red ; pale-reddish or white streak. The
presence of Ca easily shewn by the spectroscope.
CABRERITE : A cobaltiferous var. of ANNABERGITE. See below.
(Ni reaction).
ANNABERGITE (Nickel Green): NiO 37-25, As203 38-59, H2O
24-16. Acicular, efflorescent; H 1-2*5; G 3; apple-green, greenish -
white. CABRERITE is a variety containing CoO and MgO. Green
and yellowish anhydrous nickel arseniates have also been recognized
(G 4-9).
(Fe reaction, BB, magnetic slag or bead).
PHARMACOSIDERITE (Cube Ore): Fe2O3 40, AsW 43-13, H'O
16-87. Reg. (See Note at end of TABLE). H 2-5 ; G 2-9-3 ; dark-
green, yellow, brownish,; streak, paler. Mostly in minute cubes
tetrahedrally moc&fied.
11
BLOWPIPE PRACTICE.
SCORODITE : Fe'O* 34-63, As2O5 49-78, H2O 15-59. Rh. ; H 3-5-4;
G 3-1-3-3 ; dark-green, brownish, indigo-blue ; streak, paler.
ARSENIOSIDERITE : Fe2O3 39-4, CaO 13-8, As205 37-9, H20 °>-9.
Fibrous-botryoidal. H 1-2 ; G 3-9 ; brownish-yellow, with silky
lustre.
SYMPLESITE : FeO, Fe203, As'O6, IPO (25-28 per cent.). Clino-
Rh., acicular ; H 2-5 ; G 2-9-3-0 ; pale blue, green, with pearly lustre.
PITTIZITE : Fe2O*, As2O6, SO3, H2O (12-29 per cent.). Amorphous,
stalactitic. H 2-5-3; Gr 2-3-2-5; brownish-yellow, dark-brown;
streak, paler.
CARMINITE ; BEUDANTITE : Contain PbO. See above.
(MnO reaction).
CHONDRO-ARSENITE : MnO, MgO, CaO, As2O9, H2O (7-8 per cent.).
In small granular concretions of a wax yellow colour. H 3'0.
Bfi RZ ELITE : Gives Mn reaction in most examples; Ca-lines in
spectroscope ; no water. See below.
DURANGITE : Strong Na and F reactions. Orange-red. See below.
( U*0* reaction).
TROEGERITE: IPO3 65-95, As206 17-55, H20 16-50. Clino-Rh.,
tabular; H 2-2'5 ; G 3-23-3-27; lemon yellow; streak, yellowish-
white. Easily fusible.
URANOSPINNITE : U2O8 59-18, CaO 5-47, As20s 19-37, IPO 16-19.
Tetr. 1 scaly or thin tabular; H 2-2*5 ; G 3-45 ; yellowish-green.
(MgO and CaO reactions. Ca-lines well shewn in spectroscope).
BERZELITE (KUHNITE) : CaO, MgO, MnO, As2O5. Massive ; H 5
(or 4-5); G 2-5-2-55; yellow, yellowish-white. Nearly infusible.
No water evolved in bulb-tube.
PHAKMACOLITE ; CaO 24-90, As2O5 51-10, IPO 24. dino-Eh.,
but mostly acicular, fibrous, earthy, &c. ; H 1-5-2-5 ; G 2*73.
Normally colourless or white. Easily fusible.
HAIDINGERITE: CaO 28-81, As2O6 56-87, IPO 14-32. Rh.; G 2-9;
otherwise like Pharmacolite, but of rare occurrence.
WAPPLERITE: CaO, MgO, As2OB, IPO (18-20 per cent.). Clino-
R,h. ; H 1-5-2-5; G 2-5; colourless or white. Very easily fusible.
HOERNESITE is a related, but purely magnesian, arseniate (with
IPO 29 per cent.), recognized by Kengott in the kaiserlichen min.
Cabinet of Vienna.
MINERAL TABLES: — xiv. 147
(Na reaction).
DURANGITE (J. G. Brush) : Na2O, Li2O, APO3, Fe*O, MnO,
As'O5, F. Clino-Rh.; H 5; G 3-94-4-07; orange-red. Easily
fusible. With sulphuric acid, fluorine reaction. Hitherto, only-
recognized as accompanying tin ore and colourless topaz in the Pro-
vince of Durango, Mexico.
NOTE ON TABLE XIV.
This Table is composed essentially of arseniates. The exceptions comprise
& few silver sulpharsenites in which the lustre is mostly non-metallic, and the
naturally occurring arsenious acid or anhydride As203. The only minerals of
thfc Table likely to come under ordinary observation, include : (1) The " Light-
K 3d Silver Ore," Proustite ; (2) The Cupreous Arseniatea — Olivine, Clinoclase,
Liroconite, Ohalcophyllite and Tirolite ; (3) The Cobaltic Arseniate, Erythrine;
(4) The Ferruginous Species, Pharmacosiderite and Scorodite ; (5) The Lime
Arseniate, Pharmacolite ; and (6) the Lead Chloro- Arseniate, Mimetesite.
Proustite or light-red silver ore, the arsenical silver blende of some nomen-
clatures, is readily recognized by its deep or bright red colour, red streak and
adamantine lustre ; as well as by the large silver-globule obtained from it by
the blowpipe. It frequently accompanies Native Arsenic. It occurs both
crystallized and massive. The crystals are generally small, and are not always
readily made out in consequence of distortion by irregularity in the size of
corresponding planes. Commonly, they consist of hexagonal prisms terminated
by a rhombohedron (with R : K = 107°50'}, or of scalenohedrons. Small
fragments melt in the candle flame, without the aid of the blowpipe. Boiled
with caustic potash, the powder becomes immediately black, and As2S3 is
dissolved. This is thrown down, as a yellow flocculent precipitate, by a drop
or two of hydrochloric acid.
The copper arseniates are green, or more rarely blue, in colour, and, as a
rule, they detonate or deflagrate somewhat strongly when ignited on charcoal.
Olivine and Clinoclase are usually dark-green or blackish-green (though some-
times brown or brown-yellow), and both occur frequently in small crystals,
and in radiated- fibrous, reniform, and other uncrystallized examples. The
Olivine crystals are rhombic, and the Clinoclase crystals clino-rhombic com-
binations. Clinoclase is almost constantly in radiated groupings, whence its
old German name of Strahlerz. Olivine yields only 3*20 per cent. aq.
Clinoclase 7 per cent. Liroconite is very usually of a light-blue colour, though
sometimes green. It occurs mostly in very small clino-rhombic crystals which
present in general an ortho-rhombic aspect, and sometimes resemble slightly
distorted octahedrons. In the bulb-tube it yields (without decrepitation) a
large quantity of water (25-26 per cent.). Chalcophyllite is rarely in distinct
crystals, but generally in micaceous or thin tabular examples of a bright
148 BLOWPIPE PRACTICE.
emerald-green colour, with metallic-pearly lustre on the broad surfaces of the
laminae. In the bulb-tube it decrepitates strongly and yields a large amount
of water (23-32 per cent,). Tirolite or Tyrolite is unknown in crystals. Most
commonly it occurs in bright green or blue radiated examples, or in reniform
or fine scaly masses. Thin foliae are flexible. The specimens hitherto examined
contain 13-14 per cent, carbonate of lime, either in combination or as an
intermixture. The presence of Ca is readily shewn by the spectroscope^
especially if the copper be first reduced by fusion with carb. soda on charcoal,
and the resulting slag be moistened with a drop or two of hydrochloric acid.
The amount of water equals 20-21 per cent.
Erythrine, the cobaltic arseniate, is especially distinguished by its peach-
blossom red colour, and by the deep-blue glass which it forms by fusion with
borax. » It occurs in small clino-rhombic crystals, but more commonly in
bladed, acicular and efflorescent examples. The thin folise are flexible.
Easily fusible. Water, 24 per cent.
The ferruginous arseniates, Pharmacosiderite and Scorodite, distinguished
from the cupreous and other arseniates by the magnetic slag which they yield,
BB, on charcoal, are distinguished individually by their crystallization.
Pharmacosiderite is almost always in very minute cubes, truncated on alternate
angles by the triangular planes of the tetrahedron. Its colour is dark-green,
passing into brownish-yellow and brown, and the little crystals are usually in
drusy aggregations. Scorodite when crystallized is commonly in small prisms
terminated by an acute rhombic pyramid, but it occurs also frequently in
fibrous and other examples. The colour is dark-green or indigo-blue, inclining
to reddish-brown in some specimens. The hardness exceeds that of calcite,
whilst Pharmacosiderite is slightly under calcite in hardness.
Pharmacolite, the ordinary lime arseniate, is comparatively unimportant.
It occurs mostly as a white efflorescence, or in acicular crystals, on arsenical
cobalt and iron ores.
Mimetesite, chloro- arseniate of lead, is readily distinguished from other
minerals of the Table by its high sp. gr. (7 '0-7 '3), as well as by the lead
globule which it yields, BB, on charcoal. It belongs by its crystallization
and chemical formula to the Apatite group, and often passes into Pyromorphite,
the corresponding lead phosphate. The crystals, hexagonal prisms, or com-
binations of prism and pyramid, are very commonly curved into almost
globular shapes. The colour is generally yellow, more rarely grey, brown, or
green, with resino-adamantine lustre. Fused in the platinum forceps, the
bead crystallizes on cooling, but on charcoal it becomes reduced.
[U9]
TABLE XV.
[Lustre non-metallic. BB, on charcoal, antimonial fumes and deposit.]
A —On charcoal, reducible to metallic antimony and rapidly
volatilized.
(S reaction with carb. soda).
KERMESITE (Pyrostibite, Red Antimony Ore, Antimony Blende).
Sb2S* 70, Sb2O3 30. Red, bluish or brownish red, with red streak
and adamantine lustre. Rh. (or Clino Rh. *? ), but mostly acicular or
fibrous; H 1-1 '5; G 4-5 4-6. Fusible in candle-flame.
(No 8 reaction).
VALENTINITE : Sb 83-56, 0 16-44. Rh., mostly tabular or acicular.
H 2-3; G 5'3-5'6; normally white, but sometimes pale reddish or
brownish from admixtures. Becomes yellow on ignition, and melts
very easily. In the bulb-tube, sublimes entirely, if pure. SENAR-
MONTITE has the same composition (Sb2O3) and general characters,
but is Regular in crystallization. The crystals are commonly octahe-
drons, often with curved planes.
CERVANTITE : Sb2O3 47-40, Sb206 52-60. Rh.1 acicular, encrusting ;
H 3-0-4-0 (or 5 ? ) ; G 4'08. Yellow, yellowish-white. Infusible,
but reducible on charcoal. Not volatile in the bulb-tube.
(No S reaction ; aq in bulb-tube).
ANTIMONY OCHRE : Sb203, mixed more or less with Sb205, and
yielding H2O on ignition. Earthy, encrusting ; G 3'8 ; yellow, yel-
lowish-white. Reduced and volatilized on charcoal.
STIBLITE: Sb203, Sb2O5, H20 (5-6 per cent.). Compact, pseudo-
morphous after antimony glance. Yellow, yellowish-white. Reduced
and volatilized on charcoal, the reduction (as in all compounds of
Sb203 -f Sb'O5) assisted by addition of carb. soda.
B.— On charcoal partially vol , a metallic globule remaining.
(Ag reaction),
PYROSTILPNITE (Fire Blende in part): Ag (62 per cent.) Sb, S.
Clino-Rh. 1 tabular, foliated. H 2 ; G 4*2-4-3 ; orange-yellow,
brownish-red ; streak, red or yellow ; lustre pearly-adamantine. BB,
antimonial fumes and large silver-globule.
150 BLOWPIPE PRACTICE.
PYRARGYRITE ; POLYBASITE : Ag, Sb, S. Iron-black, or deep-red in
thin pieces by transmitted light. Streak, red. Lustre essentially
metallic or sub-metallic. See TABLES IV. and IX.
(Cu reaction}.
RIVOTITE : CuO, Sb2O5, mixed with carb. lime, &c. A doubtful
species. Compact j yellowish-green; H 3'5-4'Oj G 3*55-3-62
(Ducloux).
(Pb reaction).
BINDHEIMITE (Bleiniere) : PbO, Sb205, H2O (6 per cent.). A
doubtful compound. Massive, earthy, &c. ; H l-4j G 3'9-4'7.
Greyish-white, yellowish, brownish, green, &c. Often veined or
clouded in different tints.
N ADORITE : PbO, Sb2O3 -f- PbCP. Rh. , tabular. H 3 -0 ; G 7 -02 ;
yellowish or greyish-brown. Hitherto found only in .calamine
deposits in Algeria.
C.— On charcoal partially vol , an earthy mass remaining.
ROMEITE: CaO 19-5, Sb 63-8, O 16'7. In groups of small tetra-
gonal octahedrons of a yellow or reddish colour. H 5 -5 (?), G 4 '67-
4*71. The presence of Ca in the residuum, left on charcoal after
roasting, is easily recognized by the spectroscope. Part of the CaO
is commonly replaced by MnO and FeO.
NOTE ON TABLE XV.
The minerals of this Table consist chiefly of rare or obscurely known examples
of antimouial oxidea, alone, or combined with lead oxide, &o. None of these
compounds are of mineralogical importance. The only species of ordinary
occurrence referred to in the Table is the mineral Kermesite or Pyrostibite,
a compound of 2Sb2S3 with Sb203. This occurs commonly in association with
Antimony Glance, It is usually in radiating- fibrous or tufted plumose masses
of a deep bluish-red or brownish-red colour, with red streak and adamantine
(more or less sub-metallic) lustre. In caustic potash, the powder assumes a
yellow colour, and on boiling is rapidly dissolved. Fusible and volatilizable
in the caudle-flame without the aid of the blowpipe.
[151]
TABLE XVI.
[Lustre non-metallic. BB, with carb. soda strong sulphur-reaction.]
A —Anhydrous species. No water (or traces only)
in bulb-tube.
A*.— REDUCIBLE TO METAL PER SE OR WITH CARB. SODA.
(BB, a lead globule).
ANGLESITE : PbO 73-6, SO3 26-4. Rh. (V : Y 103°44') ; H 3
(or sometimes slightly lower) ; G 6-1-6-4 (commonly 6-3) ; colourless,
grey, yellowish, &c. ; streak, white. Sol. in caustic, potash. SAR-
MANITE is a supposed clino-rhombic species of similar composition.
LANARKITE : PbO, SO3 57-6 -f'PbO 424. Clino-Rh. ; H 2*0-2-5;
G 6 -5-6 -9 ; pale greenish-white, yellowish, grey. Flexible in thin
pieces. By alteration, partially converted into carbonate, and then
effervesces in acids.
LEADHILLITE : PbO, CO2 -|- PbO, SO ; effervesces in acids. See
TABLE XIII.
(Pb and Cu reactions. Flame coloured strongly green. With carb. soda, lead
sublimate. With boracic acid, copper globule).
CALEDONITE ; PbO, CuO, SO3 (CO2 and H2O by alteration ?) Rh.
(or Clino-Rh. ?) V : V 95°. Light bluish-green ; streak, greenish-
white; H 2-5-3; G 6 -4. Generally effervesces in acids.
A2.— NOT REDUCIBLE TO METAL, BB. ATTACKED OR DISSOLVED IN POWDER BY
HOT HYDROCHLORIC ACID, WITH EMISSION OF H2S ODOUR.
( With carb. soda, zinc sublimate on charcoal).
SPHALERITE or ZINC BLENDE : Zn 67, S 33. Reg. (mostly inclined
hemihedral); H 3*5-4; G 3-9-4-2. Brown, black (often red by
transmitted light), green, yellow, rarely colourless; streak, mostly
pale-brown. Many yellow examples are phosphorescent by surface-
abrasion. Practically infusible. The lustre varies from adamantine
to sub-metallic and metallic proper. See TABLES III. and X. MAR-
MATITE and CHRISTOPHITE are dark, ferruginous varieties.
VOLTZINE: ZnS 82-7, ZnO 17-3. H 3-5-4-0; G 3-5-3-8. Brownish-
red, yellow, greenish ; streak, pale-brown. Practically infusible.
( With carb. soda, red-brown cadmium-sublimate).
GREENOCKITJE : Ca 77-8, S 22-2. Hex., hemimorphic (crystals
mostly small acute pyramids, with lower half entirely replaced by;
152 BLOWPIPE PRACTICE.
basal plane). H 3-3-5 ; G 4-8-4-9. Yellow, orange, brownish,' with
yellow streak and adamantine lustre. Infusible. On ignition,
becomes deep-red whilst hot, but generally decrepitates.
( With carb. soda, strong manganese reaction}.
ALABANDINE: Mn 63-2, S 36*8. Black, brownish-black, with
greenish streak, and, in general, sub-metallic aspect. No sublimate
in closed tube. See TABLE X.
HAUERITE : Mn 46-22, S 53-78 ( = MnS2). Reg., parallel-hemi-
hedral, and thus resembling Iron Pyrites in crystallization. Dark
red-brown, brownish-black, with brownish-red streak, and, in general,
sub-metallic lustre. In closed tube, turns green, and gives sublimate
of sulphur. See TABLE X.
A*.— NOT REDUCIBLE TO METAL. NO ODOUR OF H*S EVOLVED BY TREATMENT
WITH HYDROCHLORIC ACID.* TASTELESS, INSOLUBLE.
f Entirely diss )lved, BB, by carb. soda.
(Flame, coloured apple-green).
BARYTINE (HEAVY SPAR) : BaO 65-7, SO3 34-3, a portion of the
BaO sometimes replaced by SrO or CaO. Rh. (V : V 101°40').
H 3'5 ; G 4-3-4-7 ; colourless, white, yellow, flesh-red, brown, &c.,
with white streak. BB, generally decrepitates. Fusible into a
white caustic enamel, the flame coloured pale-green. BARYTO-
CELESTINE (G 4-24) is a mixture or isomorphous union of BaO,
SO3 and SrO, SO3. BARYTO-CALCITE (G 4-0-4-3) = BaO, SO3 +
CaO, SO3. As regards the latter, see below.
(Flame coloured crimson).
CELESTINE: SrO 56-52, S0» 43-48. Rh. (V : V 103°40'- 104°10');
H 3-3-5; G 3-9-4-0; colourless, pale-blue, indigo-blue, yellowish, &c.,
with white streak. BB, generally decrepitates. Fuses into a white
caustic enamel, and imparts a crimson coloration to the flame.
ft In part, only, dissolved, BB, by carb. sr,da.
ANHYDRITE: GaO 41 -18, SO* 58-82. Rh. (Y : Y 100°30') : H
3-3-5 ; G 2-8-3. Mostly in colourless, white, bluish, or reddish
lamellar masses, with pearly lustre on cleavage planes ; streak,
white. BB, fusible into a white caustic enamel. Colours the flame-
border red, after prolonged exposure,
* The presence of Ba, Sr, and Ca, in minerals of this section, is, readily determined by the
spectroscope. See. Outline of Blowpipe Practice, page 55.
MINERAL TABLES : — XVI. 153
BARYTO-CALCITE : A compound of the sulphates of baryta and
lime. Properly, a calcareous var. of Heavy Spar, but referred to
here as being only partially soluble, BB, in carb. soda, the lime
remaining unattacked. G 4-0-4-3. Imparts a pale-green tint to the
flame-border ; but the orange-red Ca-line comes out prominently in
the spectroscope.
A*.— SOLUBLE. SALT OB BITTER TO THE TASTE.
(Ammonia reaction. BB, entirely vol.)
MASCAGNINE : Am 39-4, SOS 60-6. Rh. (V : V 121°8'), but chiefly
in white or yellowish crusts or mammillated masses on certain lavas.
H 2-2-5 ; G 1-7-1-8. Taste, sharp and bitter.
(Flame coloured violet. Red X-line well defined in spectroscope).
GLASERITE (ARCANITE) : K'O 54, SO3 46. Rh. (V : V 120°24>
but mostly in white earthy crusts. H 2-5 ; G 2*7. Taste, bitter.
BB, generally decrepitates, melts easily, and crystallizes over the
surface on cooling. APTHALOSE is a rhombohedral potash sulphate
from Vesuvius.
(Flame coloured intensely yellow. Na-line, only, in spectroscope).
THENARDITE: Na2O 43-66, SO3 56-34. Rh., but mostly in drusy
or earthy crusts and coatings of a white or greyish colour; H 2*5 ;
G 2*67. Taste, saltish, alkaline. Easily fusible, and on charcoal
reduced to sulphide, and absorbed.
(In spectroscope, green and orange-red Ca-lines, and yellow Na-line).
GLAUBERITE: Na2O, SO3 51, CaO, SO5 49. Clino-Rh.; H 2-5-3-0;
G 2-7-2-8. Taste, saltish and bitter. White, grey, yellowish, red,
<kc. Somewhat deliquescent. BB, decrepitates, fuses easily, and
becomes reduced to sulphide. In carb. soda, the lime remains undis-
solved. In water, only partially soluble.
B.— Hydrous compounds. Yielding water by ignition in
bulb-tube
Bi.— FORMING, BB, WITH BORAX A PRACTICALLY UNCOLOURED BEAD.
f Readily soluble in water, and possessing a bitter or other taste.
(On charcoal, BB, entirely absorbed. Flame coloured intensely yellow).
MIRABIUTE (GLAUBER'S SALT) : Na'O 19-3, SO3 24-8, H2O 55-9.
Clino-Rh., but mostly efflorescent, &c. ; H 1-2; G 1'4- 1 -5. Taste,
cooling and bitter.
154
BLOWPIPE PRACTICE.
(The residuum, left BE on charcoal, assumes by ignition with cobalt solution a
Jme, blue colour).
ALUM (Potash Alum, Kalinite) : K2O 9-95, APO3 10-82, SO3 33-75,
H20 4:5-48. Reg., octahedral, but commonly in white or greyish
crusts, <fec. H (crystals) 2-2-5 ; G 1 -7-1 -9. Red K-line in spectroscope.
SODA-ALUM : Na2O, APO, SO3, H2O. In white or greyish crusts,
&c. BB, strong yellow flame, and yellow Na-line in spectroscope.
AMMONIA ALUM (Tschermigite) : Am, APO8, SO3, H2O. Earthy
crusts. BB, partially vol. with strong ammoniacal odour. If pure,
no lines in spectroscope.
MAGNESIA ALUM (Pickeringite) : MgO, APO*, SO3, IPO. In
white or greyish crusts, &c. If pure, no lines in spectroscope.
ALUNOGENE (Hair-salt in part) : APO8 15-4, SO3 36, H2O 48-6.
In efflorescences of minute acicular crystals on various coals, shales.
Ac. Normally colourless, but often gre nish or brownish from
admixture with iron-vitriol or iron-alum.
( The residuum, left BB on charcoal, assumes by ignition with cobalt solution
aJlesJi-red colour).
REUSSIN : A compound of soda sulphate (Mirabilite) with 30-31
per cent, of magnesia sulphate. In white feathery crusts, &c.
Colours flame intensely yellow.
EPSOMITE: MgO 16-26, SO3 32-52, H2O 51-22. Rh. (V : V 90°38')
but commonly efflorescent, &c. ; colourless ; H (crystals) 2-2-5 '>
G l-7-l"8. After strong ignition, gives alkaline reaction. If pure,
no lines in spectroscope.
BLCEDITE (Astrakanite) : Na2O 18-65, MgO 11-95, SO3 47'90,
H2O 21-50. Clino-Rh., but mostly in lamellar masses, crusts, &c.
H (crystals) 2-5-3-5 ; G 2-2-2-3. White, grey, pale-reddish, greenish,
&c. Colours flame intensely yellow. LCEWITE is a related soda-
magnesia sulphate, but apparently distinct in crystallization, and
with only 14*66 per cent, water.
KAINITE : MgO, SO3 48-3, KC1 30, H2O 21-7.. Clino-Rh. (tabular),
but commonly in granular masses, <fec. H 2*5 ; G 2'13. Yellowish-
white, greyish. BB, with phosphor-salt and CuO, strong chlorine
reaction (azure flame). Part of the KC1 sometimes replaced by
NaCL
MINERAL TARLES I — XVI. 155
( The residuum, left BB on charcoal, assumes by ignition with cobalt solution a
light- green colour).
GOSLABITE : ZnO 28-22, SO3 27-88, H2O 43-90. Rh. (V : V
91 °5'). H (crystals) 2-2-5 ; G 2-0-2-1; colourless, greyish-white*
BB, with carb. soda, gives zinc sublimate on charcoal.
(The residuum, on charcoal, with <x>balt solution becomes on ignition dark-grey.
In spectroscope, Ca (or Ca and K) lines).
POLYHALLITE ; SYNGESITE j ETTRINGITE ; KlESERITE : Soluble in
part only, or very slowly sol. Taste, very feeble. See below,
tf Insol. or very slowly sol. in water. Taste, 0, or very feeble.
(BB, imparts a green colour to the flame-point, and gives PJ05 reaction (yellow
precipitate) with amm. molybdate in the nitric acid solution).
SVANBERGITE : Na2O, CaO, APO3, SO3, P205, H2O 6 per cent.
Hemi-Hex. (RR about 88° or 90°) j H 4-5; G 2-57. Yellow,
orange-red. Very rare, and imperfectly known.
(BB, with Co-solution, a, bright blue colour).
ALUMINITE (Websterite) : A12O3 29-77, SO3 23-23, H2O 47. In
white or yellowish-white earthy or porous masses which adhere to
the tongue ; H 1-0; G 1-7-1 '8. BB, infusible ; evolves SO2. FELSO-
BANYITE, in small groups of rhombic (pseudo-hexagonal) tabular
crystals, is related in composition, but yields 38-67 per cent, water.
ALUNITE (Alumstone) : K2O 11-33, A12O3 37-10, SO3 38-56, H20
13-01. Hemi-Hex. (R : R 89al 0'), but commonly in granular masses.
H 4-5 ; G 2-6-2-8. White, pale-reddish, yellowish, &c. Infusible;
generally decrepitates. Evolves, on strong ignition, SO2. LCEWIGITE
is identical or closely related, but yields 18-18-5 per cent, water.
(BB, with Co-solution, a flesh-red colour).
KIESERITE : MgO 29, SO3 58, H2O 13, but commonly yields more
water, from hygroscopic absorption. Clino-Rh., but commonly in
fine-granular masses. H 3 ; G 2*57. Very slowly soluble in water.
BB, infusible ; gives off SO2.
(BB, with Co-solution, a dark-grey colour. In spectroscope, Ca (orCaandK) lines)*.
GYPSUM (Selenite): CaO 32-54, SO3 46-51, H2O 20-95. Clino-Rh.
(See note at close of Table). H 1-5 j G 2-2-2-4. Colourless, white,
* These spectrmn-lines come out most distinctly when the ignited test-substance is moistened
by hydrochloric acid. See Outline of Blowpipe Practice, pp. 55-59.
156 BLOWPIPE PRACTICE.
pale-reddish, bluish, yellowish, &c.; streak, white; aspect vitrio-
pearly in crystallized and lamellar examples, silky in most fibrous
varieties, sometimes earthy. In thin pieces, somewhat flexible. BB,
becomes immediately opaque, and fuses into an opaque white bead.
On prolonged ignition, reacts alkaline, and tinges the flame-border
distinctly red.
POLYHALLITE : K20, SO3 28«93, CaO, SO 45-17, MgO, SO3 19-92,
H20 5-98. Rh., but commonly fibrous, lamellar, &c. H 3-3-5 ; G
2-7-2-77. Red, flesh-red, greyish, colourless. Partly sol. in water.
Taste, feebly bitter. BB, very easily fusible into an alkaline (hollow)
bead. Some examples give Cl-reaction with phosphor-salt and CuO.
SYNGENITE : K2O, SO3, CaO, SO3, with 5-5 per cent, water. Clino-
Rh. (tabular); H 2-5 ; G 2-6 ; colourless. BB, easily fusible, but
generally decrepitates. Partly soluble in water. Distinguished chemi-
cally from Polyhallite by absence of MgO. (See Outline of Blowpipe
Practice, page 55).
ETTRINGITE : CaO, APO3, SO3, H20 (45-82 per cent.). In delicate,
silky, hexagonal prisms on the lava of the Laacher See. G 1*75.
BB, swells up, but remains unfused. Partly soluble in water.
BS.— FORMING, BB, WITH BORAX A STRONGLY COLOURED BEAD.
t Soluble or partly sol. in water, and possessing a metallic or other taste.
(Cu reaction).
CHALCANTHITE or BLUE VITRIOL. CuO 31-85, SO8 32-07, H2O
36-08. Anorthic, but commonly in drusy or earthy crusts of a blue
or greenish-blue colour ; . streak bluish-white ; H (crystals) 2*5 ;
G 22-2-3. Taste, strongly cupreous and unpleasant. Moistened
and rubbed on a knife-blade, deposits metallic copper. PISANITE is
a cupreous Iron- Vitriol or Melanterite. LETTSOMITE and WOOD-
WARDITE are hydrated sulphates of CuO and APO3. The first occurs
in druses of deep-blue hair-like crystals ; the second in mammillated
examples of similar colour.
(Fe reaction*, BB, a magnetic slag),
MELANTERITE or GREEN VITRIOL : FeO 25-90, SO3 28-78, H2O
45 '32. Clino-Rh., but commonly in crusts and coatings on iron
ores, <fec. Pale-green, blue-green, often ochreous on surface. H
* The solution yields with Ferricyanide of potassium, or with the ferrooyanide, a deep-blue
precipitate.
MINERAL TABLES :— XVI. 157
(crystals) 2; G 1-8-1 -9. Taste, inky, metallic. PISANITE is a
cupreous variety. TAURISCITE a rhombic variety isomorphcus with
Epsomite.
COQUIMBITE : F208 28-47, SO8 42-70, H2O 28-83. Hex., but com-
monly in small granular masses. • H 2-2*5 ; G 2-2-1 ; very pale green,
bluish, greenish-white. Taste metallic, inky. The aqueous solution
deposits Fe208 on boiling.
BOTRYOGENE: MgO, FeO, Fe203, SO8, H2O (28-30 per cent.).
Cliiio-Rh., fibro-mamillated, &c. Red, orange or brownish-yellow ;
streak yellow; H (crystals) 2-2-5; G 2-1. Taste, feebly metallic.
Partly soluble in water. RCEMERITE is closely allied or identical, but
part of the FeO is replaced by ZnO.
IRON-ALUM (Feather Alum ; Halotrichite, in part) : Composition
very variable, but essentially an alum, with FeO and Fe203 largely
replacing the other bases. Greenish or brownish, in coatings and
minute hair-like crystals. See under ALUNOGENE in B1 f, above.
VOLTAITE : FeO, Fe2O3, APO3, SO8, H2O (15-3 per cent.). An
altered Iron-Alum ? Reg. ; dark-green, black ; streak, greenish -grey.
H 2-5-3-0 ; G 2-8. Slowly soluble in water. Taste, feebly metallic.
Other ferruginous sulphates, Glockerite, Pissophane, Apatelite,
Copiapite, Jarosite, &c., are insoluble or very slightly soluble in
water. See below.
(Go reaction).
BIEBERITE (Cobalt Yitriol) : CoO, SO3, H20, but part of CoO often
replaced by FeO or MgO. Isomorphous with Melanterite, but occurs
only in efflorescent coatings of a pale rose-red colour. Easily dis-
tinguished by its blue borax-glass.
(Ni reaction).
MORENOSITE (Nickel Vitriol). NiO (MgO), SO3, H2O (40-45 per
cent.). Isomorphous with Epsomite, but occurring only in efflo-
rescences of hair-like crystals or in amorphous coatings. Green,
greenish-white.
( Uranium, reaction).
JOHANNITE : UO, SO3, H2O. Clino-Rh. ; H 2-2-5; G 3-2. Grass-
green; streak paler. Slowly soluble in water. Various other uranium
sulphates (in some of which U2O3 is present) have been recognized
(Medjidite, Zippeite, Voglianite, &c.), but the composition of these
is more or less inconstant, and their characters are very imperfectly
known.
159 BLOWPIPE PRACTICE.
(Mn reaction).
APJOHNITE (Manganese Alum) : Essentially an alum with MnO
replacing part of the other bases. In hair-like efflorescences of a
pale reddish or brownish colour.
FAUSERITE (Manganese Vitriol) : MnO, MgO, SO8, H2O (42-66
per cent.). Rh. (V:V 91° 18'); H 2-2-5 ; G 1-9. Pale reddish,
yellowish-white.
f f InsoluUe, (or practically insol.y in water. Taste, 0, or very slight.
(Pb and Cu reactions. BB\ on charcoal a yellow coating).
LINARITE: PbO 55'7, CuO 19-8, SO3 20, H2O 4-5. Clino-Rh. ;
H 2-5-3; G 5-3-4-45. Azure-blue; streak pale-blue.
(Cu reaction).
BROCHANTITE : CuO 70-34, SO8 17-71, H20 11-95. Rh. 1 jT:V
104° 32'); H 3-5-4 ; . G 3-8-3-9. Emerald-green, dark-green ; streak
pale-green. KRISUVIGITE is identical. TANGITE and WARRINGTONITE
are closely related, but yield 15*33 per cent, water. All form a
deep-blue solution with ammonia.
LETTSOMITE (Velvet Copper Ore). CuO, APO8, Fe'O2 SO8, H2O
(2.3*34 per cent.). In delicate hair-like crystals of a deep blue colour.
WOODWARDITE, in blue mamillated masses, is identical.
(Fe reaction: BB, a magnetic slag or crust).
COPIAPITE : Fe208, SO8, H20 24-5 per cent. In six-sided pearly
tables, and granular masses. H 1-5; G 2-14. Yellow.
STYPTICITE : Fe2O3, SO3, H2O 36 per cent. In greenish or yellowish-
white fibrous crusts. FIBRO-FERRITE is apparently identical, but some
so-called Fibro-ferrites are soluble in water. Owing to their incon-
stancy of composition, due to alteration and intermixture, no very
strict definitions ai e possible as regards ferruginous sulphates generally.
GLOCKERITE: Fe2O8, SO-', H20 (20*7 per cent.). Stalactitic, botry-
oidal. Black, dark-brown, yellowish, dark-green; streak brownish-
yellow. PISSOPHANE, in dark-green and brown botryoidal and earthy
masses, is apparently a variety, or a closely related substance, but
yields 40-41 per cent, water. VITRIOL-OCHRE is an earthy, ochre-
yellow variety (H2O 21 per cent.).
APATELITE: Fe208, SO8, H2O (4 per cent.). In small nodular
earthy masses of a yellow colour and streak, from Auteuil, near Paris.
Chiefly distinguished by its low amount of water.
MINERAL TABLES : XVI. 159
JAROSITE : K2O 9-38, Fe'O' 47-91, SO3 31-93, H2O 10-78. Hemi-
Hex. (R : R about 89°), mostly tabular from predominance of the
basal plane, also in scaly and fine granular examples ; H 3-4 ; G
3 '2-3 -6. Dark-brown, brownish-yellow, red by transmitted light ;
streak ochre-yellow. Shews the red K-line in spectroscope.
DIADOCHITE: FeW, SO8, P205, H2O 30-3 per cent. H 2-5-3;
G l-9-2'5. Brown, brownish-yellow; streak somewhat lighter.
Mostly in mammillated, concentric-lamellar examples. BB, on char-
coal, a magnetic bead. In the forceps, tinges the flame-point green.
PITTICITE (Iron Sinter) resembles Diadochite in general characters,
but contains As206. The composition, however, varies greatly in
different examples.
NOTE TO TABLE XVI.
This Table is composed, apart from a few sulphides of non-metallic aspect,
entirely of sulphates.
Sphalerite or Zinc Blende is the only commonly-occurring sulphide referred
to in the Table. This mineral presents in many of its varieties a more or less
metallic lustre ; but in others, the light-coloured varieties especially, the lustre
is non-metallic and usually adamantine. Sphalerite is commonly in lamellar
masses (of easy cleavage parallel to the planes of the rhombic dodecahedron),
or otherwise in crystals of the Regular System. These consist chiefly of
tetrahedrons, twinned octahedrons, rhombic-dodecahedrons, and a com-
bination of rhombic-dodecahedron with a half-trapezohedron or pyramidal
0.0
tetrahedron . Sub-fibrous and granular examples are also known, and
some of these, more especially, are cadmiferous. Certain Blendes, likewise,
contain thallium in minute quantity ; and in almost all the dark Blendes small
proportions of Fe and Mn are present. Many varieties also contain traces,
and even workable amounts, of gold and silver. The more common colours
are dark-brown and black, with light-brown streak, and these dark examples
are often blood-red in thin pieces by transmitted light. Less common colours
are dark-green and yellow: colourless examples are still more rare, and
hitherto have been found only in New Jersey. Yellow varieties (especially)
often shew strong phosphorescence when scratched or abraded in the dark.
All varieties give a zinc-sublimate on charcoal if fused in powder with carb.
soda and borax ; and all emit the odour of sulphuretted hydrogen when warmed
in powder with hydrochloric acid.
Natural sulphates fall into five more or less well defined groups. These
comprise : (1) Anhydrous Prismatic Sulphates ; (2) Gypsums ; (3) Bitter-Salts
and Vitriols ; (4) Alums ; and (5) Alumstones.
The anhydrous prismatic sulphates are principally represented by Anglesite,
Barytine, Celestine, and Anhydrite. These have the common formula RO,
160
BLOWPIPE PRACTICE,
SO8, and a common Rhombic crystallisation, with V : V (the prism-angle in
front) 100° 30'— 104° 30\ according to the species.
Anglesite (PbO, SO8) occurs in small crystals, mostly colourless or greyish,
with strong adamantine lustre ; and also in small mamillated and lamellar
examples, and in earthy masses, white, yellowish, &c., arising from decom-
position of galena. The crystals are generally in drusy aggregations, and are
very brittle. They are either tabular, from predominance of B or V ; prismatic,
vertically, from predominance of V ; prismatic, transversely, from extension
of i P or £ P ; or pyramidal from preponderance of P. It much resembles the
lead carbonate cerussite, but is distinguished (when the two are not intermixed)
by blowpipe and acid reactions.
Barytine or Heavy Spar, sulphate of baryta, is very widely distributed, and
is especially abundant as a gangue or veinstone in lead, zinc, silver, and other
metallic veins. It occurs most commonly in lamellar or fibrous masses, but is
also very common in crystals. The latter are sometimes of comparatively large
size, and are almost always sharply-defined and distinct. They belong to the
Rhombic System, and present chiefly four leading types : (1) tabular, with V
•— - \j
and B, or rectangular-tabular with £ P, P, and B, as principal forms, B pre-
dominating ; (2) transversely prismatic in a macro-diagonal direction, with V
and i P as chief forms, the latter elongated ; (3) transversely prismatic in a
brachy-diagonal direction, with 4 P and P as chief forms, the latter elongated ;
and (4) pyramidal, from about equal predominance of the common front and
side polars £ P and P. More common angles are as follows : V : V 101° 40' ;
i P : £T over summit 102° 17' ; B : £ P 141° 8' ; P : P over summit 74° 36' ;
B : P 127° 18'. Barytine is commonly colourless, white, or yellow, but also
frequently grey, reddish, bluish, &c., and in some stalactitic and radio-
spherical examples, deep-brown or greyish-black. BB, it melts into a bead
which reacts alkaline after prolonged ignition, and it communicates to the
flame-border the apple-green tint characteristic of barium compounds. In
carb. soda, BB, it is rapidly and entirely dissolved. In acids, insoluble. In
Bunsen flame, after sufficient ignition, it shews the green bands of the barium
spectrum very distinctly.
Celestine, the strontia sulphate, differs remarkably from Barytine in its
geological relations, occurring very rarely in metallic veins, but chiefly in
cavities and fissures in stratified calcareous rocks. The finest crystals occur
in connection with native sulphur in Sicily. These are colourless, but when
in fibrous or lamellar masses celestine very commonly presents a pale-blue
colour, whence its name. It is also white, pale-yellowish, &c. The crystals
are Rhombic combinations, and are generally elongated in the direction of the
brachy-diagonal. More common forms comprise B, V, P, and % P, with angles
as follows : V : V about 104°, but varying from 103° 30' to 104° 30' ; P : P over
summit 75° 52' ; B : P 127° 56' ; £ P : i P~62° 40' ; B : £ F 121° 20'. BB melts,
colours the flame-border crimson, and reacts alkaline. Entirely dissolved,
MINERAL TABLES : — XVI. 161
BB, by carb. soda. Insoluble in acids. In Bunsen flame, after short ignition,
shews very distinctly the blue, orange-red, and group of crimson lines, of the
strontium spectrum. These lines come out still more prominently by crushing
the ignited or fused bead (as obtained in a reducing flame on charcoal), and
moistening the powder with hydrochloric acid.
Anhydrite, lime sulphate, is generally in lamellar, granular or columnar
masses of a white colour, though occasionally greyish or bluish, and sometimes
brick-red. Crystals are comparatively rare. They consist chiefly of com-
binations of V and V with several brachydomes or side-polars, V predominating
and imparting to the crystals a rectangular, tabular aspect. Also of com-
binations of V and P, with brachy diagonal elongation. BB, fuses easily into an
alcaline reacting bead, which imparts a comparatively feeble but distinct red
colour to the flame border. In carb. soda, BB, not dissolved. Slowly soluble
in hydrochloric acid. In the Bunsen flame (especially if first ignited and then
moistened with hydrochl. acid), it shews the green and red lines of the calcium
spectrum very distinctly.
The Gypsum Group consists of hydrated sulphates, with lime, or lime-
magnesia, and alkalies, for base. It is chiefly represented by Gypsum and
Polyhallite,
Gypsum, in analytical formula, CaO, SO3 4- 2 H2O, is a widely distributed
mineral. It occurs chiefly in Clino- Rhombic crystals and in lamellar, laminar,
fibrous, columnar, and granular masses, either colourless, or of a white, reddish,
yellowish or other tint, and occasionally red, brown, black, &c., from ochreous
or carbonaceous admixtures. Small transparent pieces become immediately
opaque if held at the edge of a candle flame, and all varieties may be scratched
by the nail. The crystals are often of considerable size. The most common,
perhaps, are combinations of the Vertical prism V with the Side-vertical or
/
Olino-pinakoid V, and the Hemi-pyramid P. The latter form occurs necessarily
as a pair of inclined planes (often curved) at each extremity of the crystal.
The V or side planes usually predominate, and thus give a somewhat flattened
aspect to most crystals. Two of these crystals are frequently united in reversed
positions, producing arrow-headed or lance-headed twins. Transparent
examples of Gypsum are commonly known as Selenite. The lustre is partly
pearly and partly vitreous, and in most fibrous examples, satin-like. The
ignition-loss (water) is nearly 21 per cent. In the Bunsen flame, the red and
green lines of the calcium spectrum come out very prominently, especially if
the ignited test-matter be moistened with a drop of -hydrochloric acid.
Gypsum, although tasteless, and thus for practical purposes regarded as in-
soluble, is dissolved in fine powder by about 450 parts of water.
Polyhallite (see composition in Table) is comparatively i unimportant. It
occurs commonly in sub-fibrous or columnar masses of .a pale reddish or
greyish colour. In water it is partially dissolved, a residuum of lime sulphate
remaining. Very easily fusible. Ignition-loss undervSjaer cent., but examples
are often mixed with clay, gypsum, &c.
12
162 BLOWPIPE PRACTICE,
The group of Bitter-Salts and Vitriols falls into three sections : a rhombic
section, with the analytical formula RO, SO3 -f 7 H2O, represented by Epsomite,
Goslarite, Morenosite ; a elino-rhombic section, represented by Melanterite.
Bieberite, &c., al*o with the formula RO, SO3 + 7H'O; and a triclinic or
anorthic section, with the formula RO, SO' + SH'O, represented by Chalcanthite
or Copper Vitriol. These compounds in their actual occurrence as minerals,
however, are of comparatively little interest, as they occur chiefly in solution
or in the condition of efflorescent coatings, &c., rarely in distinct crystalliza-
tions. All possess an intensely bitter or metallic taste, and give off sulphurous
acid on strong or prolonged ignition. The water, evolved in the bulb tube,
has thus an acid reaction.
The group of Alums, characterized by octahedral crystallization and the
general formula RO, S03 + R203, 3S03 + 24HaJ, is represented primarily by
ordinary or potassic alum, and subordinately by soda alum, magnesia alum,
iron alum, &c. These compounds in their 'natural occurrence, present them-
selves merely in efflorescent crusts and coatings, and, as minerals, are of no
special interest. All are soluble and sapid, and evolve SO2 on strong ignition.
The alum of commerce is essentially a manufactured product, derived chiefly
from decomposing pyritous shales.
The Alumstones are insoluble aluminous sulphates, represented chiefly by
Alunite and Aluminite or Websterite. Alunite is a rhombohedral potassic
species, occurring essentially in connection with volcanic or trachytic rocks.
It differs from most sulphates by its hardness, which, in granular varieties
especially, often exceeds that of fluor spar. It is infusible, but becomes
decomposed on strong ignition, and evolves SO2. In the Bunsen flame
(^specially if the ignited test-matter be moistened by hydrochloric acid), it
shews the red line of the K-spectrum very distinctly.*
Aluminite or Websterite is of little importance. It is a simple sulphate of
alumina with 47 per cent, water, mostly in white or yellowish-white earthy or
nodular masses, which adhere strongly to the tongue and are scratched by the
finger-nail. BB, infusible, but evolves SO2.
* See PART I., page 58, 59.
TABLE XVII.
[Lustre non-metallic. Easily soluble, BB, in borax or phosphor-salt. Nitric-
acid solution (on warming) yielding yellow precipitate with amm. molybdate.]
A> — Fluo-Phosphates -Chloro-Phosphates. Giving, in powder,
with sulphuric acid in glass tube, strong fluorine-reac-
tion ; or with phoephor-salt and copper oxide, BB, an
azure flame-coloration.
A*.— YIELDING METALLIC LEAD, BB, WITH GARB. SODA ON CHARCOAL.
PYROMORPHITE : PbO P20* 89*7, PbCl2 10-3, but part of the PbO
sometimes replaced by CaO, part of the P2O5 by As205, and part of
the PbCl2 by CaFl2. Hex.; H 3-5-4; G 6-9-7-0; green of various
shades, light or dark brown, ash-grey, rarely yellow or colourless.
BB, melts into a bead which crystallizes with broad surface-facets on
cooling. See Note at close of present Table.
A*.— INFUSIBLE, OR FUSIBLE ON EXTREME EDGES ONLY.
APATITE: var. 1, F luor- Apatite : CaO, P2O5 92-27, CaFl2 7'73 :
var. 2, Ghl^ApaJbite: CaO, P2O5 89-34, CaCl2 10'66. But in var.
1, a small amount (usually 0-20-0-60 per cent.) of Ca( I5 is commonly
present; whilst in var. 2, the GaCP is almost always largely replaced
by CaFl2, the latter usually averaging 4 or nearly 5 per cent, of the
entire components of the apatite. Crystal-System Hex. ; H 5*0 ;
G 2-9-3-3 ; green of various shades, greenish- white, light-red, reddish
or chocolate brown, sometimes colourless. BB, practically infusible,
or rounded only on the thinnest edges. Phosphorite, Francolite,
Osteolite, Talc-apatite, Eupychroite, are merely varieties (in some
cases more or less decomposed) of apatite proper. In these, as well
as in many unaltered crystals, <fcc., intermixed carbonate of lime is
often present. See Note at close of present Table.
WAGNERITE: MgO, P'O5, 81, MgFl2 19. Clino-Rh. ; H 5-5-5;
G 3-0-3-15 ; yellow, yellowish- white. BB, fusible on thin edges only.
Very rare. The Norwegian Kjerulfin is closely related, if not an
altered variety.
A*. -VERY EASILY FUSIBLE.
(Strong Mn reaction with carb. soda).
TRIPLITE: (FeO, MnO) P O5, R Fl2. Clino-Rh J; H 5-5-5; G
3-6-3-9; dark-brown; streak yellowish-grey. Occurs only in ch avable
164 BLOWPIPE PRACTICE.
masses of vitreo-resinous lustre. Easily fusible into a dark globule.
With carb. soda, strong manganese-reaction. Zwieselite is closely
related, but is apparently Rhombic in crystallization.
(Bed flame-coloration, and distinct Li-line in spectroscope).
AMBLYGONITE: APO3, P2O5, (LiNa)' Fl. Anorthic; H 6; G
3-0-3-12; greenish-white, greyish or bluish-green. Easily fusible
into a white opaque bead, with red coloration of the flame. With
cobalt-solution, after ignition, assumes a fine blue colour. HEBRONITE
(Montebrasite) is closely allied, but yields water on ignition. Perhaps
an altered amblygonite ]
^%The imperfectly known HERDERITE or ALLOOONITE (Rh., with pseudo-
hexagonal aspect ; yellowish- white ; H 5 ; G 2*9-3), and some varieties of
WAVELLITE (mostly in greenish-white or green radiated fibrous examples, see
under D, below), are also fluorine-containing phosphates. These assume a fine
blue colour after ignition, in powder, with nitrate of cobalt. KAKOXENE, in
yellow silky tufts (see under C1, below), shews also, in most examples, a slight
fluorine-reaction. BB, a magnetic slag.
B.— No Fluorine reaction. No water evolved by ignition in
bulb-tube-
Bl.— EASILY FUSIBLE.
(Fusion-globule magnetic).
TRIPHYLINE: Li2O, Na'O, K2O, MnO, FeO, P205. Rh., but
occurring only in cleavable masses of a greyish-green, light grey, or
grey-blue colour. H 4-5 ; G 3-5-3-6. Colours the flame distinctly
red, if moistened with hydrochloric acid, or fused with chloride of
barium, and shews the red Li-line in spectroscope.*
B2 — INFUSIBLE, OR FUSIBLE ON EXTREME EDGES ONLY.
XENOTIME: YO 62-13, P'O5 37-87, but with part of the YO
always replaced by CeO. Tetr. ; H 4-5 ; G- 4-45-4-6; yellowish,
brown, red-brown, pale-red. Scarcely attacked by boiling acid ; but,
on dilution with water, sufficient is dissolved to give a yellow
coloration to a fragment of amm. molybdate dropped into the solution
and gently warmed.
CRYPTOLITE : CeO, LnO, DiO, P'O5. Pale-yellow or reddish ; G
4'6; in minute acicular crystals in certain Apatites. PHOSPHOCERITE,
* Some examples of Triphyline shew this crimson line very distinctly per se, but in general
it is only obtained by moistening the mineral with hydrochloric acid, or mixing it in powder
with chloride of barium. The latter reagent answers perfectly, and has the advantage of being
conveniently carried in the blowpipe case.
MINERAL TABLES : — XVII. 165
in very minute, apparently Tetragonal, crystals in certain Swedish
examples of cohaltiae> is identical in composition. G 4*78 j pale
greenish-yellow.
MONAZITE: CeO, LnO, ThO, 3PfO*. Clino-Rh. ; H 5-5-5; G
4 -9-5 -3; reddish-brown, yellowish-red, pale-red. Many examples
give traces of tin by the reducing process : See page 1 7. EREMITE
(MONAZITOID) and TURNESITE are varieties. In some of these &
small percentage of Tantalic acid is present.
C.— Hydrous Phosphates. Water evolved on ignition
in bulb-tube.
GI.— MAGNETIC AFTER FUSION OR IGNITION, OR GIVING STRONG REACTION OF
MANGANESE WITH CARB. SODA.
(This section includes a series of iron or manganese-phosphates, in most of
which the composition is very uncertain, owing to changes in the oxidation of
the base, or loss or gain of water. Many of these phosphates can scarcely
rank as definite species. In the present Table they are arranged after the
average percentage of water which they contain. Where the iron is in the
condition of protoxide, the ignition-loss will necessarily be slightly lower
(about 1 per cent.) than the actual percentage of water present in the mineral).
KAKOXENE: Fe2O3 47, P'O5 21, H2O 32. In delicate tufts and
fibro-mammillated examples of a yellow colour with silky lustre. G
2 -4. BB, a dark magnetic slag.
VIVIANITE : FeO (rapidly changing into Fe2O3), P2O5, H2O 28 per
cent. Clino-Rh., but commonly in bladed and fibrous examples of a
greenish-blue or deep indigo-blue colour ; rarely colourless, and then
containing FeO only; EL 2 ; G 26-2-7. Flexible in thin pieces.
BB becomes red, and fuses into a magnetic globule, LUDLAMITE,
from Cornwall, is closely related, but has less water (17 per cent.).
STRENGITE : Fe'O3, P2O5, H2O 19-20 per cent. ; Rh., but chiefly in
fibrous mamillated examples of a bluish-red or pink colour, rarely
colourless; H 3-4; G 2-9. BB, easily fusible into a magnetic*
globule.
CHILPRENITE: MnO 10, Fe203 29, AK)3 14, P2O5 29, H2O 18.
Rh. ; H 4-5-5 ; G 3-2-3 "3. Yellowish-white, yellow, blackish-brown.
BB, intumesces, and forms a dark magnetic slag or semi-fused mass.
BERAUNITB: Fe'O3, P'O5, H*O 16-5 per cent. In radiated and
leafy examples of a red or red-brown colour and yellow streak ;
H 2; G 2-9-3; BB, fusible, magnetic*
166 BLOWPIPE PRACTICE.
HUREAULITE: MnO 41, FeO 8, P2O5 39, H2O 12. Clino-Rh.,
mostly tabular ; also coarse-fibrous, &c. H 3-5 ; G 3*2 ; yellowish-
red, red-brown, more rarely violet or reddish-white. BB, easily
fusible into a dark, feebly-magnetic globule.
HETEROSITE : FeO (changing into Fe2O3), MnO (changing into
MnGa;, P2O5, H2O 4-4 per cent. Massive; H 4-5-5; G 3 '4-3-5 ;
greenish or bluish-grey, violet, brown. BB, fusible, magnetic.
C2.— WITH BORAX, BB, A GLASS COLOURED BY COPPER OR URANIUM OXIDE-
STREAK LIGHT-GREEN OR YELLOW.
f Water-percentage 14-19.
LIME.URANITE (AUTUNITE) : CaO 6-10, U2O3 62-75, P2O5 15-47,
IPO 15-68, but sometimes, and normally, nearly 19 per cent, of
water present. Tet., or Rh. with marked tetragonal aspect, mostly
tabular from predominance of basal plane, and thus passing into
foliated examples. Yellow, greenish-yellow ; H 1-2 ; G 3-3*2 ;
BB intumesces slightly, and fuses into a dark bead with crystalline
surface. In nitric acid forms a yellow solution. URANOSPHO^RITE
is a related uranium phosphate, but with baryta in place of lime.
Yellowish-green ; G 3-5.
COPPER-TJRANITE (CflALKOLITE, TORBERNITfi) : CuO 8'43, TJ203
61-19, FO5 15-08, H2O 15-30. Tet., mostly tabular, passing into
foliated micaceous examples. Emerald-green, paler in the streak,
with metallic-pearly lustre; H 2-2 -5 ; G 3-5-3-6. BB, fusible and
reducible to metallic copper. Forms in nitric acid a yellowish-green
solution.
CHALKOSIDERITE : CuO (8-15), Fe'O3, A12O8, P3O5, H20 15 per
cent. In small, light-green, anorthio crystals. G 3*1.
ft Water-percentage 8-11.
TAGILITE: 'CuO 61-85, P2O5 27-64, H2O 10-51. Clino-Rh.? but
mostly fibrous, mammillated, &c. ; emerald-green; H 3; G 4-4-1.
BB, fusible and reducible.*
EHLITE ; CuO 67, PW 24, H2O 9. Rh. 1 but mostly in foliated
and bladed examples, with pearly lustre on cleavage surface; H 1-5-2;
G 3-94-3. Decrepitates in bulb-tube. On charcoal, reduced.!
• The reduced copper-globule is surrounded by a black coating of unreduced phosphate*
With carb. soda, perfect reduction ensues.
t The re U oed oappe^glohuje is surrounded by a black coating of unreduced phosphate^
WiUi ca.rU. soda, perfect reduction, ensues.
MINERAL TABLES : — XVII. 167
PHOSPHORCHALCITE : CuO 70-88, P2O5 21-10, H>0 8-02. Clino-
Rh., but mostly fibrous, mammillated, <fcc. ; green, blackish-green;
H 4-5-5; G 4-1- 4-3; decrepitates and blackens on ignition; fuses
to a dark bead with crystallized surface ; on charcoal, reduced.*
DIHYDRITE is closely related, but consists of CuO 69, P2O5 24*7,
IFO 6-3.
f f f Water-percentage under 4.
LIBETHENITE : CuO 66'5, PO5 29-7, H20 3-8. Rh., crystals very
small ; dark-green, blackish-green ; H 4 ; G 3'6-3'9. Decrepitates
and blackens in bulb-tube. In forceps, melts to a dark bead with
crystallized surface. On charcoal, forms a black globule surrounding
reduced copper.
#% Some examples of Wavellite, Peganite, Fischerite, and Turquoise (see
under C3, below), contain a small amount of CuO, and thus give a copper-
reaction with borax.
C3.— IN POWDER, COLOURED BRIGHT-BLUE BY IGNITION WITH
COBALT-SOLUTION.
f Water-percentage 20-40.
WAVELLITE: A12O3 38-10, P2O* 35-16, H2O 26-47, but traces of
Fluorine often present. Rh. (crystals mostly small and indistinct),
commonly in botryoidal radiated-fibrous examples of a pale green,
greenish-white, or yellowish-white colour; H 3*5-4 ; G 2-3-2-5. BB,
swells up, separates into fibres and becomes opaque-white, but does
not fuse.
FISCHERITE — PEGANITE — YARISCITE: Hydrated aluminous phos-
phates closely related to Wavellite. Rhombic in crystallization, but
commonly in radiated fibrous examples of a green or white colour.
H 3-5; G about 2 -5. BB, like Wavellite. Planerite, Striegisan,
Richmondite, Evansite and Zepharoviehite are probably altered
examples. These minerals can only be distinguished by accurate
chemical analysis. Many give a slight copper-reaction. The per-
centage of water is as follows : Variscite 23, Peganite 24, Wavellite
26-5, Zepharoviehite 27, Fischerite 29, Richmondite 35, Evansite
40-42.
CALAITE or TURQUOISE : Al'O3 47, P2O* 32-5, H2O 20-5. In light-
blue and bluish-green amorphous masses; H 6; G 2'6-2'8. BB,
*The reduced copper-globule is surrounded by & black coating of unreduced phosphate.
With carb, soda, perfect reduction ensues.
108 BLOWPIPE PRACTICE,
decrepitates, and often blackens, but remains unfused. Many
examples shew traces of copper.
f f Water-percentage under 13.
LAZULITE : MgO, FeO, Al'0, PO*, H*O (5-7 per cent). Clino-
Rh. (but scarcely differing from Rhombic in aspect and measure-
ments). Blue, bluish-white; H 5-6; G 3-3'2. BB, exfoliates and
crumbles, but does not fuse.
BEELINITE — TBOLLEITE — AUGELJTE: Hydrated aluminous phos-
phates of a blue or greenish-blue colour. Water percentage : 4, 6,
and 12 '5 respectively. Obscurely known or doubtful species.
C«.-IN POWDER, COLOURED PALE-RED, GREEN, OK DARK-GREY BY IGNITION
WITH COBALT-SOLUTION.
f With Co-solution, pale-red.
LUNEBERGITE: MgO, P*O5, B'O3, H'O (30-23 per cent.). In
white, fibrous and earthy masses. H 1-1-5 ; G 2 -05. Easily fusible,
with green coloration of the flame-border. With sulphuric acid and
alcohol, gives the green flame characteristic of B2O3.
STRUVITE : a hydrous phosphate of ammonia and magnesia. Rh.
(hemimorphic). Colourless, yellowish, pale-brown ; H 1 -5-2 ; G
1-6- 1'8. In peat-bogs, guano-deposits, &c. Evolves ammoniacal
fumes on ignition.
f f With Co-solution, light-green.
(BB, on charcoal with carb. soda, a zinc sublimate}.
HOPEITE: ZnO, P2O5, HO? Rh. ; greyish-white; H 2'5-3; G
2*7-2 '8. BB, fusible into a white bead. Some examples shew
presence of cadmium.
1 1 f With Co-solution, dark-grey.
BRUSHITE: CaO 32-6, 1*0*41-3,11*0 26-1. Clino-Rh.; colourless,
yellowish; H 1*5; G 2*2. Metabrushite and Isoclase are related
products. In all, the presence of C»O is readily determined by the
spectroscope,
OHURCHITE: CaO, CeO, DiO, P'O5, H'2O (15 per centA Clino-
Rh. (?) radiated. Greyish-white, pale-red ; H2-5-3; G o'L Imper-
fectly known,
MINERAL TABLES 1 — XVII. 169
NOTE TO TABLE XVII.
This Table is represented by Phosphates, or by Phosphates combined with
Fluorides or Chlorides. Its more important species may be referred broadly
to the following groups : (1) Apatites ; (2) Triplites; (3) Alumina Phosphates;
(4) Iron and Copper Phosphates ; (5) Uranium Phosphates.
The Apatite group is characterized by its Hexagonal crystallization, and by
the common formula 3 (3 RO, P2O5) + R (Fl, Cl)2. It is represented by
Apatite and Pyromorphite, and also by the related arseniate and vanadiate,
Mimetesite and Vanadinite, the latter described, in a technical work of this
kind, under other Tables. Apatite, often known commercially as "Phosphate,"
is largely employed in the manufacture of Superphosphate of lime, so exten-
sively used as a fertilizer. It commonly presents itself in cleavable masses or
hexagonal prisms of a light or deep green colour, but is frequently chocolate-
brown, red, or almost colourless. Green and reddish tints are often inter-
mingled. The edges of the crystals are frequently rounded. The more
common crystals are simple six-sided prisms with large basal plane, or these
with a slight pyramidal replacement on the basal edges ; but Canadian crystals
(when unbroken) shew complete pyramidal terminations, without any basal
plane. As regards composition, Apatite includes two leading varieties :
fluoride of calcium being present in one, and chloride and fluoride in the other.
Both are readily dissolved, in powder, by nitric acid, and the diluted solution
yields a yellow precipitate with amm. molybdate, especially on being warmed.
Very carefully neutralized by ammonia, it gives also a yellow precipitate with
nitrate of silver. Heated with a few drops of sulphuric acid, both varieties,
as a rule, give a marked fluorine-reaction, the evolved fumes exerting a strongly
corrosive action on glass. Before the blowpipe, Apatite is infusible, or is
rounded only on the thinnest edges. The powder moistened with sulphuric
acid tinges the flame border pale green, thus shewing the presence of phosphoric
acid ; and in the spectroscope the green and red Ca-lines are readily produced,
but this latter reaction is best obtained by moistening the powder with hydro-
chloric acid.
Pyromorphite is essentially a chloro-phosphate of lead. It is commonly in
groups of small crystals of a dark or light green, brown, or grey colour. The
so-called yellow varieties are mostly Mimetesite, or mixtures, at least, of
phosphate and arseniate. The crystals are chiefly simple six-sided prisms,
frequently barrel-shaped by curvature. The name Pyromorphite refers to the
peculiar blowpipe reaction presented by the mineral. Per se (if free from
arseniate), it is not reduced, but melts easily into a light-yellowish or greyish
bead which crystallizes over the surface on cooling. Pyromorphite is easily
soluble in nitric acid,
The group of Triplites is principally represented by Triplite, Triphyline,
and Amblygonite, practically anhydrous phosphates or fluo- phosphates of easy
fusibility. Triplite is mostly in dark-brown oleavable masses, giving marked
reactions of manganese and fluorine. Triphyline is also in cleavable masses,
but of a light colour, essentially pearl-grey, greyish-blue, or greyish-green.
170 BLOWPIPE PRACTICE.
It gives no marked fluorine reaction, but if moistened with hydrochloric acid,
or mixed in powder with chloride of barium, it shews in the spectroscope the
crimson Li-line very prominently. Amblygonite (see the Table) is a rare
mineral. It gives both Fl and Li reactions.
The group of hydrated alumina-phosphates is chiefly represented by Wavellite
and Kalaite, the latter more generally known as the Turquoise. Wavellite
occurs rarely in distinct crystals, but is generally in botryoidal and radiated-
fibrous examples of a green or greenish-white colour, and is found more
especially in. argillaceous slates. It is soluble in acids, and also in a strong
solution of caustic potash. Before the blowpipe, it exfoliates, becomes opaque
white, and tinges the flame pale-green, but does not fuse. Most specimens
give with sulphuric acid a slight fluorine-reaction. When pure, the water-
percentage = 26£. Kalaite or Turquoise occurs chiefly in small nodidar or
flattened masses of a bright blue, bluish -white, or bluish-green colour.
These scratch glass slightly ; but many so-called turquoises are merely pieces
of fossil bone coloured by copper oxide. In these, the hardness rarely exceeds
3 ; and they give off in most cases a marked ammoniacal odour on ignition.
In the true turquoise the water percentage = 20£.
Vivianite, Phosphorchalcite, and Libethenite are the chief representatives
of the group of Iron and Copper Phosphates, characterized by their peculiar
blue and green colours. Many of these are isoniorphous with arseniates of
corresponding formulae. Vivianite, normally, is colourless, but the FeO, pre-
sent in it, becomes rapidly converted into Fe^O3, and the mineral assumes a
blue or bluish-green colour, with pale blue or greenish streak. It is commonly
in flat-fibrous or bladed masses. It reddens on ignition, and inelts into a dark-
grey magnetic bead. Easily soluble in acids. Blackened in a hot solution of
caustic potash. Water percentage = 28. Phosphorchalcite occurs commonly
in groups of small clino-rhombic crystals and in fibrous examples of a blackish-
green or emerald-green colour, paler in the streak. It blackens in the bulb-
tube, and evolves about 8 per cent, water. Before the blowpipe it commonly
decrepitates, and then melts into a black globule containing in its centre
reduced copper. If the dark globule be fused with a small cutting of metallic
lead it crystallizes on cooling. Libethenite closely resembles it in general
characters and in its blowpipe reactions, but is rhombic in crystallization^ and
yields only 3*77 per cent, water. Its colour also, as a rule, is much less bright.
It is isomorphous with the arseniate Olivenite.
The group of Uranium Phosphates includes only the Autunite or Lime-
Uranite, and the Chalkolite (Torbernite) or Copper- Uranite. The lime-uranite
is distinguished by its pale yellow or yellowish-green tint, and the copper-
uranite by its splendid emerald-green colour. Both occur commonly in small
lamellar or micaceous examples, and in groups of small tabular crystals.
These latter are rhombic in the lime-uranite (but with strongly tetragonal
aspect), and tetragonal in copper-uranite. Both species fuse more or less
easily, and the latter gives reduced copper. Both species dissolve readily in
nitric acid, and are decomposed by caustic potash with abstraction of their
phosphoric acid. Water percentage 15-16.
[171]
TABLE XVIII.
[Lustre non-metallic. Easily dissolved BB by borax or phosphor- salt. Green
coloration of flame by treatment with sulphuric acid and alcohol.]
A-— Anhydrous Species. No water evolved (or merely
traces) by ignition in bulb-tube-
BORACITE : MgO 27, B2O3 62-5, MgCl2 10-5. Reg. (see Note at
end of Table) ; H 7 ; G 2*9-3 ; colourless, pale greenish, reddish,
<fec. ; streak white. Mostly in small crystals imbedded in anhydrite
or gypsum. BB fusible with intumescence, tinging the flame green.
With CuO and phosphor-salt, gives chlorine-reaction. Slowly dis-
solved by hydrochloric acid. RHODIZITE (in small crystals on some
Siberian tourmalines) is regarded as a lime boracite. H 8 ; G 3'3.
LUDWIGITE: MgO, FeO, Fe2O3, B2O3. In fibrous or prismatic
masses of a dark-green or greenish-indigo colour ; H 5 ; G 4 ; BB,
fusible slowly into a dark magnetic bead. The only examples
hitherto recognized occur with magnetic iron ore in the Bannat.
B.— Hydrous Species, yielding water on ignition.
Bl.— DISTINCTLY SOLUBLE AND SAPID.
SASSOLINE (Boracic Acid) : B2O3 56-45, H20 43-55. Clino-Rh. or
Anorthic (?), but essentially in small pearly-white scales and tabular
examples, sometimes stained by ferruginous matter. H 1 ; G 1 '4-1 '5 ;
bitter-acid taste, soapy to the touch. BB tinges the flame green, and
melts with intumescence into a hard clear glass.
LARDERELLITE (Hydrated Borate of Ammonia) : In small rhombic
or rectangular plates and scales of a white colour. Scarcely soluble,
except in hot water, and thus almost tasteless. See below, under B2."
BORAX or TINKAL : Na2O 16-2, B2O3 36-7, H2O 47'1. Clino-Rh. ;
H 1-5-2-5; G 1-7-1-8; colourless, or stained brown, yellowish, &c.,
by impurities. Taste, slightly alcaline. BB, intumesces and melts
easily, but (as regards natural or crude varieties) the glass is dark or
more or less coloured. Moistened with sulphuric acid, or with
glycerine, it tinges the flame green.
B3.— PRACTICALLY INSOLUBLE AND WITHOUT TASTE; OR DECOMPOSED BY
BOILING WATER ONLY.
f No marked Mn or Fe reaction.
STASSFURTITE (Massive and slightly altered BORACITE ?) : In fine-
granular or fibrous masses of a white or yellowish-white co our.
172 BLOWPIPE PRACTICE.
Yields 0-5-1 per cent, water on ignition : composition otherwise as
in Boracite. H 4-5-5 ; G 2-9-3-0. Readily fusible.
SZAILBELYITE : MgO, B*O*, H'O (7-12-5 per cent.). In small
globular masses of radiated-fibrous structure and white colour; H
3-5 ; G 2-7. Easily fusible.
HYDROBORACITE : CaO, MgO, B2O8, H2O (26 per cent.). In
crystalline, radiated-fibrous or leafy masses of a white or pale reddish
tint. H 2 ; G 1 -9-2. Very easily fusible. Shews red and green
Ca-lines in spectroscope if moistened with HC acid.
BOROCALCITE : CaO, B2O3, H*O (35-5 per cent). Clino-Rh. ?
Mostly in snow-white acicular crystals and incrustations. Very
easily fusible. BECHILITE is closely related, but yields less water
(2)75 per cent.). Both shew Ca-lines in spectroscope when
moistened with HC acid. PRICEITE, a milk-white chalky borate of
lime, with 20*3 per cent, water, from Oregon, is probably identical,
the amount of water in these earthy borates being very inconstant.
ULEXITE (BORONATROCALCITE) : Na'O 6-80, CaO 12-21, B2O3 45-66,
H2O 35 '33. In white, mainillated and fibrous masses. G 1*8. Very
easily fusible with yellow coloration of the flame. Decomposed, in
powder, by boiling water. TINKALZITE and CRYPTOMORPHITE are
closely related substances.
LARDERELLITE : Ammonia 127, B2O* 68-6, H20 187. In white
shining scales or small crystalline plates resembling Sassoline. Solu-
ble in hot water. Yielding ammoniacal fumes on ignition. Fusible
with strong intumescence.
1 1 BE, marked reaction of Iron or Manganese.
SUSSEXITE : MnO, MgO, B2O3, H2O (9 per cent.). In white, or
pale-reddish, silky-fibrous masses. H 25-3; G 3'42. Very easily
fusible, with green flame-coloration.
LAGONITE: F2O3, B2OS, H2O (1273 per cent). In yellow, ochreous
masses from the boracic-acjd lagoons of Tuscany.
NOTE TO TABLE XVIII,
This Table, apart from Boraoic Acid, is composed exclusively of Borates,
distinguished readily from other compounds by the peculiar yellowish-green
coloration which they impart (when moistened with sulphuric acid) to the
flame of alcohol. Many of these minerals are still imperfectly known, and are
MINERAL TABLES : — XVIII. 173
apparently of somewhat inconstant composition, more especially as regards the
hydrous species. Boracite and Tinkal (crude Borax) are the principal repre-
sentatives of the Table.
Boracite [2 (MgO, B'O3) + Mg Cl2] occurs essentially in small hemihedrally-
modified crystals of the Regular System, remarkable for their high degree of
hardness, which equals that of ordinary quartz. Hence they scratch glass
very distinctly. They are generally colourless, but sometimes present a pale
grey, greenish or yellowish tint, and are always assoriated with anhydrite,
gypsum, or rock salt. The most simple consist of the cube truncated on the
alternate angles, and thus presenting a combination of cube and tetrahedron.
Very commonly the cube-edges are also truncated by the planes of the rhombic
dodecahedron ; and the latter form predominates in some crystals. As in most
other hemihedrally-modified minerals, Boracite is pyro-electric. The substance
known (from its locality) as Stassfurtite appears to possess essentially the
same composition, except that it yields a small amount of water on ignition.
This substance is thus commonly regarded as massive Boracite, but its hardness
is comparatively low, usually under 5. It occurs mostly in granular or sub-
fibrous masses of a chalky- white colour. Tinkal or crude Borax (Na20, 2B208
-t- 10 H20) is a product of certain salt lakes, and is mostly in the form of small
granular or crystalline masses of a greyish or brownish-white colour. Mois-
tened with sulphuric acid, or simply with glycerine, it imparts a distinct green
coloration to the flame. Per se, it colours the flame intensely yellow, and
melts with great intumescence into a more or less clear bead. In the bulb-tube
it evolves 47 '2 per cent, water. Its crystallization is Clino-Rhombic, and the
ordinary borax crystals have a remarkable resemblance, even in their angle
values, to those of Augite.
[174]
TABLE XIX.
[ Lustre non-metallic. Easily dissolved, BB, by borax or phosphor-salt. Giving
with the latter reagent and CuO an intensely azure-blue or green flame
(01., Br., or I reaction)].
A.— Soluble in Water. Sapid.
AI.-NO WATER <OR MERELY TRACES) IN BULB-TUBE.
f Entirely dissolved BB by carb. soda.
ROCK SALT (Halite) : Sodium 39-31, Chlorine 60'69. Reg., with
cubical cleavage; H 2 ; G 2-1-2-2; colourless, white, grey, greenish,
red, violet, &c. ; streak white ; taste, strongly saline, sometimes
bitterish from presence of chloride of magnesium and other im-
purities. BB, generally decrepitates, colours the flame strongly
yellow, melts, and in prolonged heat sublimes.
SYLVINE : K 52-35, Cl 47-65, but generally contains NaCl. Reg. ;
H 2; G 1-9-2; colourless, greyish, reddish, &c. ; taste, like that of
rock salt. BB, easily fusible, colouring the flame violet if pure. In
spectroscope, even if impure from NaCl, &c., it shews the red K-line
very distinctly (See Part I., p. 58-59).
SAL AMMONIAC (Chloride of Ammonium) : Reg., but commonly in
crusts and earthy coatings; H PO-2 ; G 1'5-1'G; white, brownish,
yellowish. Taste, pungent, saline. Entirely volatilizable without
fusion. Ignited with caustic potash, gives off ammoniacal fumes.
f f BB with carb. soda only partially attacked, an undissolved mass
remaining.
CHLOROCALCITE (Chloride of Calcium). In white crusts on some
Vesuvian lavas, often associated with thin scales and crystals of Iron
Glance. Shews red and green Ca-lines in spectroscope very distinctly.
TACHHYDRITE: CaCP 21, MgCl2 37, H2O 42. In rounded cleav-
able masses of a yellow colour assoriated with Carnallite, Anhydrite,
&c. Very deliquescent. Easily fusible. Ca-lines in spectroscope.
CARNALLITE KC1 26-8, Mg Cl2 34-2, H2O 39. Rh., with pseudo-
hexa<*onal aspect, but commonly in fine granular examples of a white
colour, or sometimes red from intermixed Fe2O3 or scales of Iron
Glance. Deliquescent. Easily fusible. Shews red K-line in spectro-
scope, together with Na-line, part of the KC1 being generally replaced
MINERAL TABLES: — XIX. 175
by NaCl. Found essentially in salt deposits. Some examples are
said to contain traces of Thallium, also Caesium and Rubidium.
KREMERSITE : Am, K, Fe, 01, H*O. In small octahedrons, of a
red colour, on some Vesuvian lavas. Easily soluble. Deliquescent.
B.— Yielding reduced metal, BB, with carb. soda on charcoal.
f BB a silver globule.
KERARQYRITE (Horn Silver Ore) : Ag 75'3, Cl 24-7. Reg., but
commonly in granular masses and coatings of a grey, greenish, or
violet-brown colour, and waxy aspect. H 1-1 -5 ; G 5*6 ; very sectile.
BB melts with bubbling, and on charcoal is easily reduced.
BROMARGYRITE : Ag 57*4, Br 42*6. Yellow, yellowish-green. Sec-
tile, and otherwise like Kerargyrite, but giving green and blue flame
by fusion with phosphor-salt and CuO. Fused with bisulphate of
potash in a small test-tube, it forms a blood-red globule which becomes
yellow when cold, and turns green on exposure to sunlight. Chloride
of silver (Kerargyrite) under this treatment, gives an orange-red bead
which becomes yellowish-white on cooling, and dark-grey on exposure.
Iodide of silver forms an amethyst-red globule which turns dingy-
yellow on cooling, and does not undergo further change on exposure.
See Appendix to Part I, page 90. Microbromite, EmboHte, and Mega-
bromite are isomorphous chloro-bromides, containing, respectively,
69*8, 66 9, and 64-2 per cent, silver. These (and intermediate vari-
eties) resemble Kerargyrite in general characters.
IODARGYRITE ; Ag 46, I 54, yellow, sectile, like Kerargyrite in
general characters, but giving emerald-green flame with phosphor-salt
and CuO. Fused with bisulphate of potash in closed tube, it forms
a dark amethystine globule, which turns greyish yellow on cooling.
Slight fumes of Iodine are also evolved. Torconalite is a rare com-
pound of Ag I and Hg I. It yields a sublimate of mercury by fusion
with reducing agents (dry carb. soda, neutral ox. potash, &c.) in
closed tube.
t f BB, copper globule and reactions.
NANTOKITE : Cu 64, Cl 36. White or colourless, normally, but
often greenish externally from partial conversion into the oxy-chloride
Atacamite. In small granular and disseminated masses with cubical
cleavage. H 2 ; G 3*9. Fusible, and in chief part volatilizable, BB,
colouring the flame intensely blue. Soluble in ammonia and in acids.
176 BLOWPIPE PRACTICE.
ATACAMITE: Cu6l2 CuO, H20 (12 J — 22J per cent). Bh., but
mostly in small grains of a deep-green colour. H 3-3*5 ; G 3-7-3-77.
Fusible and reducible, colouring the flame blue. Soluble in ammonia
and acids. Atelite (from Vesuvius) and Tallingite (from Cornwall)
are closely related compounds, the latter blue in colour. Atlasite
(from Chili) is apparently Atacamite converted in chief part into
green carbonate.
PERCYLITE : CuCP, Pb Cl2, CuO, PbO, H20. Reg (crystals very
small) ; sky-blue. Fusible and reducible, with strong coloration of
flame and lead sublimate on charcoal. Hitherto only found with
alluvial gold in Mexico.
1 1 1 Pb or Bi globule and yellow coating BB with carb. soda on
charcoal.
COTUNNITE : Pb 74*5, Cl 25'5. Eh, (crystals acicular) ; H 1-5-2 ;
G 5 '24 ; white, with adamantine lustre. Fusible and volatilizable.
MATLOCKITE : PbCl2 55-5, PbO 44-5. Tet. Yellowish or greenish ;
H 2-5 ; G 7'2. BB, decrepitates and fuses. With carb. soda,- easily
reducible. Very rare. Hitherto only found in Derbyshire with lead
carbonate and flu or spar.
MENDIPITE : PbCP 38'4 PbO 61 '6, but commonly in part altered
to carbonate. In small sub-columnar or fibroas masses; Rh.?;
H2-5-3; G 7-0-7-1. BB decrepitates, fuses, and on charcoal is
reduced. A rare mineral.
PHOSGENiTE(Kerasine; Corneous lead ore) : PbCl251, PbO, CO2 49.
Tet.; yellowish-white, yellow, greenish, grey; H 2-5-3; G 6-0-6-3.
Easily fusible into a yellowish bead with somewhat crystalline surface.
With carb. soda, lead globules and yellow sublimate. In acids, soluble
with effervescence. Very rare. Schwartzembergite (from the Atacama
Desert) is a related compound containing Iodide of lead. Colour,
yellow.
DAUBREITE : BiCP 22-5, Bi2O8 72-6, H2O 3-8, with small amount
of Fe2O3, &o. From Bolivia. Characters undescribed.
C.—No reduced metal BB on charcoal, but mercurial subli-
mate with carb. soda in closed tube.
CALOMEL: Hg 85, Cl 15. Tet.; yellowish-white, grey; H 1-2;
very sectile ; G 6-4-7 ; BB entirely vol. Blackens in caustic potash ;
soluble in nitro-hydrochloric acid, bnt not in nitric acid alone.
COCCINITE (?) : Hg I2. Scarlet-red ; Tetragonal. Doubtful as a
naturally-occurring species.
MINERAL TABLES: XIX. 177
NOTE ON TABLE XIX.
This Table consists entirely of Chlorides and Oxy-Chlorides. Other chlorine
compounds combined with phosphates, &c., will be found in preceding Tables.
The only important species, or those of tolerably frequent occurence, belonging
to the present Table, consist of Rock Salt, Kerargyrite or Corneous Silver Ore,
and Atacamite.
Rock Salt or Chloride of Sodium is widely distributed in the form of beds,
in strata of various geological periods, and, in solution, in sea-water and
numerous mineral springs. It occurs also as a product of sublimation in many
volcanic regions. Normally, it is colourless and transparent ; but is very
generally of a red, greenish, grey, violet or other colour, from intermixed
impurities. Its crystals belong to the Regular System, and consist chiefly of
simple cubes, or of aggregations of small cubes presenting a hopper-shaped
aspect. Other forms (the octahedron, &c.), are comparatively rare. The
cleavage is cubical, and strongly marked. Lamellar, granular, and sub-fibrous
examples are also abundant. These are very frequently associated with
gypsum and gypsiferous clay. Although normally anhydrous, rock salt (more
especially in its less pure varieties) absorbs moisture from the atmosphere, and
runs gradually into deliquescence. It dissolves in somewhat less than 3 parts
of water, and it possesses the peculiarity of being about equally soluble in hot
and cold water. Most examples decrepitate very strcfngly on ignition. From
other chlorides it is readily distinguished by its saline taste and cubical
crystallization and cleavage, combined with its intensely yellow flame-color-
ation.
Kerargyrite, often known as "Horn Silver" or "Corneous Silver Ore," is
readily distinguished by the large globule of silver obtained from it by the
blowpipe, and by its waxy aspect, sectility, and shining streak. It gives also
reduced silver if moistened and placed in contact with a piece of zinc. It
occurs mostly in compact masses or thin layers of a pearl-grey, greenish or
blueish colour, turning brown on exposure. Unattacked by nitric acid, it
dissolves more or less readily in ammonia.
Atacamite is a hydrated compound of chloride and oxide of copper, but of
somewhat unstable composition. In some examples the water equals 12-13 per
cent. , and in others it is as high as 22£ per cent. The mineral by its green colour
and general aspect resembles certain cupreous arseniates and phosphates, but
from these it is distinguished by the azure-blue coloration which it commu-
nicates to the blowpipe flame, as well as by the precipitate formed in its nitric
acid solution by nitrate of silver. As seen in mineral collections, it is generally
in the form of a blackish -green or deep emerald-green sand. Its crystals are
small, vertically- striated prisms, and rectangular octahedrons, of the Rhombic
System. V : V = 112° 18'. Cleavage brachydiagonal.
13
[178]
TABLE XX.
[Lustre non-metallic. Readily soluble BB in borax or phosphor- salt. Wanned,
in powder, with sulphuric acid, evolve glass-corroding fumes. ]
A.— Fusible.
t Anhydrous, or yielding merely traces of moisture on ignition in
bulb-tube.
FLUOR SPAR (Fluorite) : Ca 51-3, F 48-7. Reg., essentially cubi-
cal (see Note at end of Table), cleavage octahedral; H 4; G 3-1-3-2;
colourless, violet, yellow, pale-green, deep bluish-green, rose-red, &c.,
with white streak. In most cases phosphorescent when heated. BB,
generally decrepitates, fuses into a white enamel, which tinges the
flame-border distinctly red, and reacts alkaline, after prolonged
ignition. Ratofkite is a mixture of fluor spar and marl, of a dull
greyish-blue colour.
CRYOLITE : Na 32-8, Al 13, F 54-2. Anorthic, but mostly in
lamellar masses with nearly rectangular cleavage; H 2*5-3 ; G 2-9-3-0;
white, or sometimes slightly yello wis h or reddish ; streak white ;
brittle. Melts in candle-flame into a white enamel. BB on charcoal,
leaves a white crust which becomes blue on cooling after ignition
with cobalt solution. Soluble in boiling solution of caustic potash.
Shews strong Na-line in spectroscope. Chiolite (Tetragonal), Nip-
holite, Arksutite, and Fluellite, are related compounds of similar
aspect. In Arksutite part of the Na is replaced by Ca.
SELLAITE: Mg 38-7, F 61-3. Tet.; colourless. H 5;'G 2-97.
Easily fusible into a white enamel. Becomes pale-red by ignition
with cobalt solution. Very rare. Accompanies anhydrite at the
Gerbulaz glacier in Savoy.
LEUCOPHANE : CaO, BeO, SiO2, NaF. Rh., but commonly lK
lamellar, cleavable masses. H 3*5-4, G 2 -9-3. Greenish-grey,
yellow. Phosphorescent when heated or broken. BB, very easily
fusible. MELINOPHANE (Meliphanite) is a closely related species of
a yellow colour, but Tetragonal (?) in crystallization.
t f Yielding water by ignition in bulb-tube.
PACHNOLITE : Na 10-35, Ca 17-99, Al 12-28, F 51-28, H2O 8-10.
Clino-Rh. (?). In minute twin-crystals in cavities of Cryolite.
Colourless, strongly shining. BB, crumbles and fuses into a white
MINERAL TABLES : XX. 179
enamel. In bulb-tube falls into powder and yields 8 per cent, water.
In spectroscope shews Na-line, and green and red Ca-lines. Thom-
senolite is closely related or identical.
PROSOPITE : Ca, Al, Si, F, H20. Anorthic; colourless; H 4-4'5;
G 2 -9. Often earthy from decomposition. Sometimes altered into
fluor spar. An imperfectly known species accompanying Iron Glance
at Altenberg, Saxony. When transparent and crystalline, yields
14P84 per cent water.
B— Infusible.
FLUOCERITE : Ce, F. ; Hex. (crystals, small, tabular), but mostly in
granular examples of a pale-red or yellowish colour. H 4-5 ; G 4*7.
Whitens or becomes yellow on ignition. BB, infusible. Hydro-
Huocerite is closely related (if not an altered fluocerite) but yields on
ignition about 5 per cent, water.
YTTROCERITE : Ca, Ce, Y, La, Di, Er, F, H2O. In crystalline-
granular masses of a light greyish- violet or blue-grey colour, with
imperfect (tetragonal) cleavage. BB, infusible.
PARISITE; HARMATITE: Fluorides combined with carbonates; hence
effervescing in acids. See Table XIII.
NOTE ON TABLE XX.
This Table consists essentially of Fluorides. Other Fluor-compounds com-
bined with phosphates (Apatite, Triplite, &c.) will be found in Table XVII.
Fluo-silicates (apart from Leucophane, placed here on account of its ready
solution, BB, in phosphor-salt and borax) belong to one of the succeeding
Tables: XXIV-XXVlt
Fluor Spar is the only commonly-occurring or generally distributed mineral
belonging to the present Table. It occurs very commonly with ores of lead,
zinc, and silver, more especially in mineral veins ; but is also found in cavities
and fissures in limestone and other stratified rocks. It usually forms groups
of distinct crystals, but sometimes presents itself in columnar, sub-fibrous,
lamellar, and compact examples. The crystals as a rule consist of simple
cubes, or of cubes slightly bevelled on the edges by the planes of a tetrakis-
hexahedron (mostly OC 3). In many examples the cube-faces present a four-
fold series of striae, meeting in a point at or near the centre of each face.
These striae, lines of growth in the formation of the crystal, indicate the edges
of a suppressed tetrakis-hexahedron, so to say. Fluor spar is often colourless,
but more frequently it presents an amethystine, pale-green, yellow, or deep
blue-green colour, and occasionally a rose-red or pearl-grey tint. The cube
edges by transmitted light often show a shade of colour more or less .distinct
180 BLOWPIPE PRACTICE.
from that of the faces ; and columnar or fibrous examples are frequently zoned
in different tints. In all varieties the streak is white. Hardness between
that of calcite and apatite, or equal to 4 of the ordinary scale. Sp. gr. 3 '15-3 '2.
Most examples when moderately heated exhibit a green or bluish phosphor-
escence ; but, if a fragment be heated rapidly, decrepitation almost invariably
ensues. By fusion, BB, a white enamel is produced. This tinges the flame
red, and reacts alkaline after sufficient ignition. The red and green Ca-lines
show prominently in the spectroscope, if a small splinter be held for a few
minutes in the outer edge of a Bunsen-flame.
[181]
TABLE XXI.
[Lustre non-metallic. Readily dissolved BB by borax or phosphor-salt.
Warmed in a test-tube with sulphuric acid, evolve orange-red or brownish
nitrous fumes.]
A.— Anhydrous Species. Entirely soluble BB in carb. soda.
NITRE (Saltpetre); K20 46'53, N2O5 53-47. Rh. (Y : Y 118° 49');
H2; G 1*9-2-1; normally colourless. Easily soluble in water;
taste, saltish, cooling. BB fusible with intumescence, colouring the
flame-border clear-violet. On charcoal, deflagrates and is absorbed.
NITRATINE (Chile Saltpetre, Soda Nitre): Na2O 36-47, N2O5 63-53.
Hemi-Hex. (R : R about 106°) H 1-5-2 ; G 2-l-2'2 ; normally colour-
less, but often brownish or reddish from impurities. Easily soluble ;
taste, saltish, cooling. Deliquescent. Colours flame intensely yellow;
otherwise like potash-nitre.
B — Hydrated Species. In carb. soda, BB, only partially
soluble.
NITROCALCITE : CaO 30-76, N205 58-80, IPO 10-44. In white or
greyish earthy efflorescences on the walls of limestone caverns, cellars,
&c. Soluble ; deflagrating by ignition on charcoal, leaving a white,
earthy, alkaline-reacting crust.
NITROMAGNESITE : Mg 0 24'10, N2O» 65-10, H2O 10-80. Occurs
with, and closely resembles, Nitrocalcite ; but the white crust, left BB
on charcoal, exhibits a pink tinge after ignition with cobalt-solution.
NOTE TO TABLE XXI.
This short Table comprises the three or four representatives of the group of
Nitrates hitherto recognized as minerals. All are soluble and sapid. By
ignition with organic bodies, they detonate more or less violently ; and when
warmed with sulphuric acid, or fused with bisulphate of potash, they evolve
reddish or brownish nitrous fumes. The bases (magnesia excepted) are readily
recognized by the spectroscope. Soda nitre (often erroneously called " cubical
nitre") is distinguished also from ordinary or potash nitre hy its crystallization
in small rhombohedrons, its deliquescence, and its property of communicating
a deep yellow coloration to the Bunsen or blowpipe flame. In the spectroscope,
many examples shew the red K-line as well as the Na-line, and the presence
of lime ia also sometimes revealed (see Part I., page 55).
[182]
TABLE XXII.
[Lustre non-metallic. Easily dissolved BB by borax or phosphor-salt. Forming
by fusion with carb. soda and nitre an alkaline salt partly soluble in
water, the solution assuming a blue, brown, or green colour by boiling
with hydrochloric acid and a piece of tin or zinc. .
A —Anhydrous Species. Yielding no water (or merely traces
of moisture) by ignition in bulb-tube.
A» -GIVING LEAD GLOBULES OR OTHER FUSIBLE METAL, BB, WITH CARB. SODA
OR ALONE.
f With Borax, BB. a bright-green glass.
(Streak, strongly-coloured. )
CROCOISITE (Crocoite): PbO 69, CrO8 31. Clino-Rh. (see Note at
close of Table). H 2-5-3; G 5-9-6; red; streak orange-yellow. BB,
generally decrepitates ; fusible and reducible, under slight detonation,
on charcoal. Produces chlorine fumes with hydrochloric acid.
Forms a brown or yellow solution with caustic potash.
PHOENICITE : PbO 77, CrO3 23. Rh. (crystals tabular, indistinct),
mostly bladed or fibrous, accompanying Crocoisite. Red; streak,
red; H 3-3-5 ; G 5-75. Fusible and reducible.
VAUQUELINITE : PbO 61-48, CuO 10-95, CrO 27-57. Clino-Rh.
(crystals very small, indistinct), commonly in coatings and botryoidal :
H 2-5-3 ; G 5-5-5-8. Dark-green, greenish-black ; streak green. BB,
intumesces slightly ; fusible and reducible. With borax in R. F.
(especially on addition of tin) forms a brick-red opaque bead from
presence of copper. Laxmannite is a variety in which both CrO3 and
P2O5 are present ; but this is probably the case in most varieties of
Vauquelinite.
DECHENITE : PbO 54-95, Y?O5 45-05. Mostly in small botryoidal
masses or groups of minute indistinct crystals; H 3-5 ; G 5-82 ;
reddish-yellow, brown; streak, yellow or orange. Fusible and
reducible.
EUSYNCHITE : essentially a lead and zinc vanadate, resembling
Dechenite in colour and general aspect.
DESCLOIZITE : essentially a lead vanadate of a dark-green or
greenish-black colour, with bands of yellow or brown.
PUCHERITE : Bi2O3 71-74, V2O5 28-26, but often showing traces of
P205 and As20s. Rh. (crystals very small) ; red, brown ; H 4 ;
MINERAL TABLES : — XXII. 183
G 6-25. BB, decrepitates, and yields reduced metal, with yellow
ring on charcoal. Soluble in hydrochloric acid, with development of
chlorine fumes, the red or yellow solution yielding a precipitate on
dilution.
(Streak white or indistinctly coloured.)
VANADINITE: PbO 70-83, V2O5 19-35. PbCP 9-82. Hex. (iso-
morphous with species of the Apatite group); H 3; G 6'8-7'2.
Yellow, reddish, brownish. BB, decrepitates, throws off sparks, and
gives reduced lead. With phos. salt and CuO, gives azure flame.
f f With Borax, BB, no green coloration; but green or blue glass with
phosphor-salt in RF.
WULFENITE: PbO 61-4, MoO3 38-6 Tet.; H 3; G 6-7 ; yellow,
yellowish-grey, red (the latter colour due apparently to presence of
lead chromate), rarely colourless. BB, decrepitates, melts and gives
reduced lead.
STOLZITE: PbO 49, WO3 51. Tet. (see Note at end of Table);
H 3; G 7-9-8-1 ; grey, also green, reddish, and brown. BB, melts
easily into a bead which crystallizes on cooling. On charcoal in RF,
reduced.
A«.— NO REDUCED LEAD BB ON CHARCOAL.
f BB, no magnetic globule.
SCHEELITE: CaO 19-45, WO8 80-55. Tet. (see Note at end of
Table); H 4-5-5; G 5 '9-6-2; colourless, greyish, pale-yellow, some-
times red, brown, or greenish ; streak white. BB, fusible on the
edges, or in thin splinters only.
TUNGSTIC OCHRE : W 79-3, 0 20-7. In earthy coatings of a yellow
or greenish colour. BC, infusible, blackens. Insoluble in acids ;
soluble in ammonia.
MOLYBDIC OCHRE : Mo 65-7, O 34-3 In earthy, yellow crusts and
coatings. BB easily fusible. On charcoal, absorbed (if pure). Easily
soluble in hydrochloric acid.
f t BB, magnetic globuU.
WOLFRAM : MnO, FeO, WO3. Dark-brown, reddish-brown, with
dark streak. In Clino-Rhombic crystals and lamellar masses, which
present in most cases a sub -metallic lustre. H 5-5-5; G 7-1-7-55.
BB fusible to a magnetic globule with crystalline surface. With
carb. soda, strong manganese-reaction. See Table IX.
184 BLOWPIPE PRACTICE.
B— Hydrous Species. Yielding water by ignition in bulb-tube.
(Cu reaction.)
YOLBORTHITE : CaO, CuO, V205, H20 (5 per cent.). Hex.; green,
greenish-yellow; streak, yellow; H 3; G 3'5. BB, blackens, and
fuses on charcoal into a dark slag containing reduced copper.
(Cu and Pb reactions.)
MOTTRAMITE : CuO, PbO, Y2O5, H2O (37 per cent.). In dark
crystalline coatings with yellow streak ; H 3 ; G 5*9. On sandstone
from Cheshire. PSITTACINITE (from Montana) is a related compound
in green sub-crystalline and botryoidal coatings, with 8 J per cent H20.
NOTE TO TABLE XXII.
This Table is composed essentially of Chromates, Vanadates, Tungstates,
and Molybdates. The two first may generally be distinguished from other
compounds by the clear emerald-green glass which they form BB with borax
in a reducing flame. The colour conies out in its full purity as the glass cools.
If fused in a platinum spoon with carb. soda and nitre a partially-soluble salt
results. This, in the case of Vanadates, becomes blue when warmed with a few
drops of hydrochloric acid. Chromates, thus treated, give a green solution.
See also the reactions of the latter described in PART I. of this work, page 49.
Tungstates (in the absence of colouring oxides) form BB with phosphor-salt in
the RF a fine blue glass, whilst with borax the glass is of a yellowish or
brownish colour. Molybdates give with phosphor-salt in the RF a fine green
glass. See also the distinctive reactions of these bodies with hydrochloric
acid and zinc, as given in PART I, pages 46, 47, 62.
With the exception of Wolfram (a species which commonly presents a sub-
metallic aspect, and thus belongs more especially to Table IX. ) no mineral of
this Table can be regarded as of common occurrence. Attention, however,
may be directed to the following : the chromate Crocoisite, the molybdate
Wulfenite, and the tungstates Wolfram, Stolzite, and Scheelite.
Crocoisite is readily distinguished by its fine red colour and orange-yellow
streak, and by the emerald-green glass which it forms BB with borax*. It
occurs commonly in groups of small or acicular crystals, and in granular
masses and coatings. The crystals are Clino-Rhombic combinations ; most
commonly, vertically-striated prisms terminated by the two planes of an acute
heini-pyramid ; or the same prism terminated by a very acute front-polar or
hemidome, thus closely resembling an acute rhombohedron.
* Deceptive specimens are occasionally made by placing a piece of quartz in a crystallizing
solution of bichromate of potash.
MINERAL TABLES : XXII. 185
Wulfenite (molybdate of lead) occurs in small Tetragonal crystals, mostly
of a yellow or yellowish-grey colour, but orange-red in some chromium or
vanadium- containing varieties. The crystals are either tabular or more or less
flattened parallel with the base, or are otherwise small pyramidal combinations.
As pointed out by Von Kobell, a beautiful azure-blue coloration originates if
the finely-powdered mineral be warmed with concentrated sulphuric acid in a
porcelain capsule, and some alcohol be then added.
Stolzite (tungstate of lead) and Scheelite (tungstate of lime) crystallize also
in the Tetragonal System, but the latter often occurs in crystals of half an inch
or more in length, usually a simple square-based pyramid, measuring 130° 33'
over the base or middle edge. Stolzite has a very high sp. gr., 7-'9-8'l, and is
usually grey or brownish in colour, more rarely green or red. Scheelite has a
sp. gr. of 5 '9-6 2, and is commonly grey or greyish-yellow, though occasionally
also brown, red, or green. Both, when warmed with nitric acid, leave a yellow
residuum of WO3, soluble in caustic alkalies.
Wolfram is readily distinguished from the other minerals of the Table by
its dark-brown or red-brown colour and streak ; and by the magnetic globule
which it yields, before the blowpipe. With carb, soda, also, it gives a strong
reaction of minganese. Its crystals, as a rule, are of comparatively large size.
As regards their general character, sw Note to T^ble. IX,
[186]
TABLE XXIII.
[Lustre non-metallic. Easily dissolved BB by borax or phosphor-salt, but not
yielding any reaction of the preceding Tables.]
A.— Streak or Powder distinctly coloured.
A*.— MAGNETIC, OR BECOMING SO AFTER STRONG IGNITION.
f Anhydrous species.
MAGNETITE (Magnetic Iron Ore) : FeO 31, Fe2O3 69. Black, with
black streak. In octahedrons and other crystals of the Regular
System, and in lamellar and granular masses, rarely earthy. H 5*5-6 -5 ;
G 4-9-5-2. Lustre, commonly sub-metallic. See Table IX.
MAGNOFERRITE : MgO, Fe20s. In small black octahedrons, as a
product of sublimation of Yesuvian fumeroles. Streak, dark -brown ;
strongly magnetic ; G 4*65. Accompanies thin, tabular crystals of
Iron Glance.
JACOBSITE : MgO, MnO, Mn2Os, Fe2O». Reg. ; granular ; black ;
streak, reddish -black ; H 5'5-6'0; G 4-74-4-77 ; strongly magnetic;
practically infusible.. Strong Mn reaction BB with carb. soda. In
crystalline limestone from Sweden.
FRANKLINITE : ZnO, MnO, Fe203. Reg., but commonly in small
rounded masses. Black ; streak, brown or brownish-black. More or
less magnetic in most examples. H 6-6-5; G 5-0-5-1. Lustre
mostly sub-metallic : See Table IX. BB, in powder, with carb. soda
and borax on charcoal gives a sublimate of ZnO. With carb. soda,
also, strong Mn reaction.
CHROMITE : FeO, MgO, APO3, Fe20s, Cr20s. Reg., but commonly
in granular masses. Brownish-black; streak, dark -brown. Some-
times magnetic. Infusible. With borax, BB, fine green glass.
Lustre, commonly sub-metallic. See Table IX.
ILMENITE (Titaniferous Iron Ore): Fe203, Ti20s, but FeO also
present in some varieties. Hemi-Hex.; iron-black, mostly with sub-
metallic lustre. H 5-6 ; G 4-3-5-2, commonly about 4'9. The
hydrochloric acid solution, diluted, and boiled with a piece of tin or
zinc, becomes at first colourless and then violet. See Table IX.
RED IRON ORE (Haematite, Red Ochre, &c.). Fe203, with 70 per
cent. Fe. Hemi-Hexagonal; but when of non-metallic aspect, mostly
in fibrous-botryoidal, lamellar, or earthy examples. Red, brownish or
MINERAL TABLES: — XXIIL 187
bluish-red, with cherry-red streak. H 5-6, or lower (1*5-3) in earthy
and sub-earthy varieties; G 4-8-5*3. BB, blackens and becomes
magnetic. Fusible only in fine splinters. See also Table IX.
•f* 1* Hydrous species. Yield water by ignition in bulb-tube.
BROWN IRON ORE ( = Gcethite, Limonite, Stilpnosiderite, Lepi-
dokrokite, Yellow Ochre, &c. These, although commonly ranked as
distinct species, cannot properly be regarded otherwise than as
varieties of Brown Iron Ore, only differing from one another by their
percentage of water, a character by no means absolutely constant) :
Fe2O3 + m H2O, with Fe 60-63, and H2O 10-15 per cent. Eh.
(Gcethite), but mostly in fibrous-botryoidal, massive, and ochreous
examples. Dark-brown, light-brown, brownish-yellow, with yel-
lowish-brown or dull yellow streak ; H 3-5-5-5 (but lower in ochreous
and earthy varieties) ; G 3-2-4-2, commonly about 3.8-4-0. BB, yields
water, blackens, and becomes magnetic. Fusible in thinnest splinters
only. TURGITE is a closely related compound, but has a red streak,
and yields only 5-5 '5 per cent, water. G 3*5-4 '5.
OXALITE (Humboldtine): FeO 42*10, Oxalic Acid 42'10, H20 15-80.
In hair-like crystals, fibrous and earthy examples, of a yellow colour ;
H 2 ; G 2*1-2*25. BB, blackens, becomes magnetic, and then becomes
converted into red iron-oxide. If a particle be a fused into a bead
of borax, coloured blue by copper oxide, the latter becomes rapidly
reduced to Cu2O, and the glass becomes opaque red, or shews red
streaks, on cooling. By this character, Oxalite is readily distinguished
from yellow-ochre.
AS.— YIELDING, BB, WITH CARB. SODA ON CHARCOAL, A DISTINCT SUBLIMATE
AND METALLIC GLOBULES.
MINIUM (Mennige, Red Lead) : Pb 90*7, O 9-3. Earthy; or pseudo-
morphous after galena or cerussite ; red ; streak, orange-yellow ; H 2
(or less); G 4*6-4*8. BB, darkens, and fuses easily; on charcoal
reduced. In HC1 acid becomes transformed into white PbCl2, with
evolution of chlorine fumes. Partly soluble in dilute nitric acid,
leaving residuum of puce-coloured PbO2. Insoluble in caustic potash.
MASSICOT (Litharge; Bleigliltte): Normally, Pb 92*8, O 7*2, but
always impure from presence of Fe2O8, &c. Fine scaly, earthy;
sulphur-yellow, orange-yellow ; paler in the streak; G 7'8-8'0. BB,
easily fusible and reducible. Soluble in hot solution of caustic
potash, and reprecipitating partly in crystalline scales.
188 BLOWPIPE PRACTICE.
BISMUTH OCHRE : Bi 89-7, O 10-3. In yellow, grey, or greenish
crusts on Native Bismuth, <fec. ; G about 4-5. Fusible into a yellow
crystalline bead ; on charcoal reducible.
ZINCITE (Spartalite) : Gives zinc sublimate with carb. soda, but
no metallic globules. See below.
A« -WITH CARB. SODA ON PLATINUM WIRE, DISTINCT MANGANESE REACTION.
f Anhydrous Species.
(BB, zinc sublimate on charcoal. Streak, orange-yellow. )
ZINCITE (Spartalite): Normally, Zn 80'3, O 19'7, bnt always con-
tains a certain percentage of Mn2O3. Hex., but commonly in lamellar
or granular examples, often partly coated by white zinc-carbonate ;
red; streak yellow; H4; G 5'5-5'7. Infusible. Soluble in acids.
(BB, no sublimate ; no copper reaction. Colour and streak, black or dark-brown. )
BRA UNITE ; HAUSMANNITE : In small crystals (mostly Tetragonal
octahedrons) or granular examples of dark-brown or iron-black colour
and sub-metallic lustre G 4 -7-4 -9. See Table X.
PYROLUSITE : MnO2. Iron-black, very soft, mostly in fibrous
masses of essentially sub-metallic lustre. ; infusible. See Table X.
(BB, with borax in RF, an opaque-red cupreous bead.]
CREDNERITE : CuO 43, Mn'2O3 57. In iron-black, cleavable masses
of essentially sub-metallic lustre. See Table X.
1 1 Hydrous Species.
MANGANITE : Mn2O3, H2O. In dark steel-grey or iron-black
crystals and other examples of essentially sub-metallic (or metallic)
lustre. H 3'5-4 ; G 4-4. See Table X.
PSILOMELANE : MnO, MnO2, HO2, in somewhat variable propor-
tions, with part of MnO replaced by BaO, K20, &c. (See Note on
page 119). In black, granular or sub-fibrous masses, with brownish-
black streak and more or less dull, earthy aspect; H 5-6 ; G 4-0-4-4-
Infusible, or fusible on the edges in some examples. Occasionally of
sub-metallic lustre. See Table X.
WAD : MnO, Mn2O3, H2O, in variable proportions, part of the MnO
always replaced by BaO, CaO, or K2O. Properly, a mere mixture
or decomposition product. In brown or black, earthy, scaly, stalac-
titic, or botryoidal examples, occasionally inclining to sub metallic in
lustre, H 1-0-3-0; G 2-2-2-7. Practically infusible. Grogroiliteis
a mixture of similar character.
MINERAL TABLES : XXIII. 189
PYROCHROITE (weathered examples) : MnO, H20, mixed with
carb. lime, <fec. Brown or black, in small druses in magnetic iron
ore. An imperfectly known substance. Normally, white and pearly :
see under § B, below.
(BB, with borax, strong copper reaction.)
LAMPADITE (Kupfermanganerz) : CuO, MnO, BaO, CaO, Fe203,
MnO2, H20. Properly, a mixture or product of decomposition.
Amorphous; black or brown; H 2-0-3-5; G 3-0-3-3. Infusible;
soluble in HC1 acid, with development of chlorine fumes. Kupfer-
schwarze and Pelokonite are related mixtures.
ASBOLAN : CuO, CoO, K'O, BaO, Fe2O3, MnO2, H2O. Resembles
Lampadite or Wad in general characters, but contains cobalt oxide.
Rabdionite is a similar cobalt-holding mixture.
A*.— GIVING COPPER REACTION, BUT NO MARKED REACTION OF MANGANESE.
CUPRITE (Red Copper Ore, Ruby Copper): Cu 88-8, O 11-2 ( = the
suboxide Cu2O). Reg., commonly in small octahedrons or rhombic
dodecahedrons often coated with malachite, also massive, &c. Red,
bluish-red, with lustre frequently inclining to sub-metallic ; streak,
red; H 3-5-4 ; G 5-7-6-0. BB, tinges the flame green, blackens,
melts, and on charcoal is reduced. Soluble in hydrochloric and in
nitric acid, also in ammonia. See Note to Table IX. Tile Ore is a
more or less earthy variety, mixed with Fe2O3, &c.
HYDRO-CUPRITE : Cu2O + aq. A doubtful species, in orange-yellow
coatings on magnetic iron ore from Pennsylvania. Recognized by
Genth.
MELACONITE (Black Copper Ore): Cu 79-85, O 20-15 (=CuO).
In black earthy coatings on certain copper ores, also massive and in
pseudomorphous cubo-octahedrons. H l'O-3'O; G 6-2-6-3. BB,
fusible and reducible. See TENORITE (the same compound, but with
metallic or sub-metallic lustre, from Vesuvius), in Table IX.
A*.— COLOURED STREAK OR POWDER, BUT NO REACTIONS OF FE, PB, MN, OR CU
AS IN THE PRECEDING SECTIONS.
(JBB, with borax, strong Co-reaction.)
HETEROGENITE : CoO, Co20s, H2O (21 per cent.?) mixed with
quartz, brown iron ore, &c. Black or dark-brown ; massive, botry-
oidal, earthy. A product of decomposition resembling Asbolan (see
above) but giving no copper reaction.
100 BLOWPIPE PRACTICE.
(BB, with borax, strong Ni reaction. )
BUNSENITE : Ni 78-6, O 21-4. Reg. (minute octahedrons); H 5'5 ;
G 6*4 ; brownish-green, yellowish-green. Infusible. With carb. soda
on charcoal reducible to magnetic grains.
( Uranium reaction. Soluble in nitric acid, the diluted solution giving with
ammonia a yellow precipitate.)
t In bulb-tube no water, or traces only.
PITCHBLENDE : UO, U2O3, more or less impure from presence of
Fe, Pb, As, &<:. In black or greenish-black granular masses or
disseminated grains ; H, commonly, about 5, but varying from 4 to
6 ; G 5-0-8-0. Infusible.
t f In bulb-tube more or less water.
CORACITE : Impure variety of Pitchblende from Lake Superior.
Black ; streak, grey or greenish-grey; H 4-5 ; G 2-4-5-0. Commonly
mixed with CaO CO2, SiO2, &c.
GUMMITE : U2O3, IPO, mixed with CaO, MgO, Fe2O3, P2O5, SiO2,
&c. In small granular masses, strings and scattered grains; H 2-5-3*5 ;
G 3'9-4'3 ; yellow or yellowish-red ; streak, yellow. Infusible. Eli-
asite (red-brown, with yellow streak) is identical or closely related.
URAN OCHRE : IPO3, H20, but always more or less impure, and
commonly mixed with uranium sulphate. In earthy or fine-fibrous
crusts of a yellow colour, on examples of Pitchblende.
B.~ Streak-powder uncoloured.
BW REMAINING WHITE ON IGNITION IN BULB-TUBE.
t Anhydrous Species.
PERICLASE : Mg 60, O 40. Reg. (in minute octahedrons, cubo-
octns., or cubes); cleavage, cubical ; H 6*0 ; G 3-65-3-75 ; dark-green ;
vitreous ; infusible. Hitherto only found at Monte Somma in ejected
limestone masses.
1 1 Hydrous Species.
BRUCITE : MgO 69, H2O 31, but often partially converted into
carbonate. Hemi-Hex. (R : R 82° 22', but crystals mostly tabular
from predominance of basal plane). Commonly, however, in scaly,
foliated, and sub-fibrous masses. H 2; G 2 -3-2 -4; white, greenish-
white ; lustre pearly on B plane. Infusible. Nemalite is an asbesti-
form, fibrous variety, white or pale-bluish in colour.
MINERAL TABLES : XXIII. 191
VOLKNERITE (Hydrotalcite) : MgO, APO3, FevO«, CO2, H2O. A
mixture of Brucite with alumina-hydrate, <fec., or a product of decom-
position. White '} foliated, or in tabular hexagonal crystals '} H 2 ;
G 15 '0-2 '1. BB, exfoliates, but remains unfused.
B«.— BLACKENING ON IGNITION IN BULB-TUBE.
(After strong ignition, assume a pink colour by treatment BB with cobalt
solution).
BRUCITE : MgO, H3O. Occasional examples : see above. Alkaline
reaction after ignition.
( With carb. soda, BB, strong manganese-reaction).
PYROCHROITE : MnO 79-8, H2O 2O2. In white, foliated masses,
forming strings in certain examples of" magnetic iron ore, but
weathering brownish-black from conversion of the MnO into higher
degree of oxidation. BB, blackens ; infusible.
(Ca-lines in spectroscope, and alkaline reaction, after ignition).
WHEWELLITE: CaO 38-36, C2O3 49-31, H20 12-33. Clino-Rh. ;
in small (commonly twinned) crystals on certain examples of Calcite.
Colourless; lustre vitreo-adamantine ; H2-5-2-0; G 1'83; infusible;
by gentle ignition converted into CaO, CO*.
NOTE ON TABLE XXIII.
This Table is composed essentially of Oxides. The more commonly occurring
spjecies, belonging to it, may be grouped in four series, as follows : — (1), Iron
Ores and related compounds ; (2), Manganese Oxides ; (3), Red Zinc and
Copper Oxides ; and (4), the magnesia hydrate, Brucite.
The Iron Ore group comprises, chiefly, (i) the anhydrous species of Regular
crystallization, Magnetite, Franklinite, and Chromite (with common formula
KO, Pt203) ; (ii) the anhydrous Hemi-Hexagonal species, Haematite and Ilmenite
(with common formula R203) ; and (iii) the hydrous species, conveniently ranked
together under the common name of Brown Iron Ore (with common formula =
R^O3 + m H'O). All the species of this group become magnetic after ignition
or semi-fusion, and several are magnetic in their normal condition. In most
cases the finely powdered ore dissolves without much difficulty in hot hydro-
chloric acid, but Chromite, Ilmenite, and titaniferous-holding Magnetite are
exceptions. The two latter in the form of very fine powder generally yield to
slow digestion (in a small, covered beaker on a sand bath, the acid being kept
just at the boiling point), but Chromite (unless mixed with magnetite) is very
slightly attacked. It may be decomposed however (sufficiently for determina-
tive purposes) by gentle fusion, in tine powder, with a mixture of carb. soda,
192 BLOWPIPE PRACTICE.
borax, and nitre. By this treatment an alkaline chromate, soluble in water,
is formed. The solution, decanted from the insoluble residuum, may then be
evaporated to dryness, and the resulting deposit fused with borax for the pro'
duction of a chrome-green glass. The presence of chromium may also be
shewn by the deep green coloration produced by addition of sulphuric acid
and alcohol : see PART I., page 49.
Comparatively few examples of Magnetite are referrible to the present
Table, as in most specimens of that mineral the lustre is unmistakably metallic
or sub-metallic (see TABLES VIII. and X.). Some examples, however, are
obscurely metallic in aspect. These are black in colour, with black streak, "
and strongly magnetic. Commonly in granular or lamellar masses, with G
averaging 5'0. When crystallized, in octahedrons and rhombic dodecahedrons.
Franklinite and Chromite much resemble examples of Magnetite with
obscurely metallic lustre. They are mostly in black, granular masses, with
normally dark brown or red brown streak, but the latter is often black from
presence of magnetite, or greenish from intermixed chloritic or pyroxenic rock-
matter. Franklinite is often strongly magnetic (probably from presence of
Fe304). Chromite is only occasionally magnetic, and its specific gravity falls
below 4 '6, averaging .usually 4 '3 or 4 '4. Franklinite with carb. soda, BB,
forms a turquoise enamel (Mn reaction), and gives oh charcoal (if treated in
powder with carb. soda and borax) a sublimate of ZnO. Chromite with borax
gives (on cooling) a fine green glass. See also its reactions described above.
Ilmenite resembles the above minerals by its black colour and brownish or
black streak, as well as by its frequent occurrence in granular or scaly granular
masses ; but its crystals are rhombohedral combinations closely resembling
those of Haematite (R : R 85031'). It is most readily distinguished by the
deep amethystine colour which results when its hydrochloric acid solution
(somewhat diluted) is boiled for a few minutes with a piece of tin.
Haematite occurs under several more or less distinct conditions ; but in most
cases it presents a metallic or well-marked sub-metallic aspect, and is thus
referred to in preceding Tables (see Notes to TABLES VIII. and X.). The
examples belonging more especially to the present Table commonly come
under the designation of Red Iron Ore, of which Reddle . or Red Ochre is an
earthy variety. In these, the streak is always distinctly red, and the colour
either brick-red, brownish-red, or bluish-red, the lustre in the latter case
merging into sub-metallic. The harder examples are very frequently in fibro-
botryoidal masses. BB, in the RF, all blacken and become magnetic.
Brown Iron Ore includes several so-called species or sub-species, compounds
of Fe203 with variable amounts of water. All yield a yellow or yellowish-
brown streak ; and all become red by ignition with free access of air (especially
in powder), the water being driven off. Ordinary varieties assume a bright
red colour on ignition, but varieties which contain much manganese give a
dull-red or chocolate-red powder. Before the blowpipe in a reducing flame,
all become black and magnetic, and fine splinters exhibit fusion. Practically,
these compounds may be referred to three series : — (i) a series, typified by
Goethite, in which the water averages 10 per cent., the formula being Fe30*,
MINERAL TABLES : — XXIII. 193
H26 ; (») a second series, typified by Limonite, the formula of which may be
written Fe'O3, 3 H20, with 14 to. 15 per cent, water; and (Hi), a series of
Bog ores and Ochres containing 20 per cent, or more water, and having part
of the iron in the condition of FeO combined with Immic or other organic
acid. No very strict lines of demarcation can be drawn, however, between
these varieties. Gcethite, although frequently in fibrous and other examples,
occurs occasionally in thin-scaly and acicular crystals of the Rhombic System.
The other Brown Ores are unknown in true crystals, although cubes and other
pseudomorphs derived from Iron Pyrites are not uncommon. They occur
chiefly in fibro-botryoidal, granular, and earthy masses. Many of the fibrous
examples present a silky lustre, and some are comparatively light in colour.
Many brown ores, also, shew a variegated surface-tarnish.
The group of Manganese Oxides — referrible as regards some examples to
the present Table — includes the comparatively rare species Braunite and
Hausmannite, characterized chiefly by occurring in small Tetragonal crystals
of a brownish-black colour and more or less sub-metallic aspect (see TABLE
X.); certain examples of Pyrolusite and Manganite, occurring mostly in dark
fibrous masses or crystal groups, usually of metallic or well-marked sub-
metallic lustre (see TABLES VIII. and X.); and the amorphous Psilomelane,
with the earthy, ochreous mixtures known as Wad. The two latter alone
belong properly to this Table ; and Psilomelane in many of its examples
presents a more or less metallic aspect (see TABLE VIII. ). These manganese
oxides, if warmed in powder with hydrochloric acid, cause the evolution of
chlorine fumes, a character by which they are readily distinguished from bodies
of similar aspect. The green-blue enamel which they form, BB, with carb.
soda, is also highly distinctive. Ignited by a Bunsen-flame and examined by
the spectroscope, nearly all examples shew green Ba-lines, and Psilomelane
and many Wads shew in addition the red K-line, and occasionally the crimson
Li-line. (See Foot Note, page 119).
Pyrolusite and Wad are of low hardness, and thus soil more or less dis-
tinctly. Wad yields water on ignition ; Pyrolusite is anhydrous. The other
manganese oxides of natural occurrence range in hardness from about 4'0
(Manganite) to 5 '5 or 6'0. Psilomelane and Manganite yield water on
ignition : Braunite and Hausmannite are anhydrous ; but, as already remarked^
these latter species scarcely require notice in the present Table, as their lustre
in ordinary examples is at least sub-metallic.
The group of red zinc and copper oxides includes merely Zincite and Cuprite.
Zincite or Red Zinc Ore, ZnO (with part replaced by MnO), is chiefly dis-
tinguished by its red colour, orange streak, and infusibility. With carb. soda
and borax, BB, on charcoal, it gives a characteristic zinc sublimate, and also
a strong reaction of manganese. It occurs chiefly in cleavable and scaly-
granular masses, usually associated with Frankliuite. The crystallization is
Hexagonal, with basal cleavage, but crystals are rarely met with.
Cuprite (Red Copper Ore or Ruby Copper) occurs commonly in octahedrons
(often with sunk faces) and in rhombic dodecahedrons and other forms and
combinations of the Regular System, frequently converted into green carbonate
14
194 BLOWPIPE PRACTICE.
on the surface. It is also found in acicular groups and in lamellar and other
masses ; and in a dull, sub-earthy condition (mixed with Fe'203, &c. ) forming
the so-called "Tile Ore." Its more distinctive characters are its red colour
and streak, and its easy reduction, BB on charcoal, to metallic copper. It
dissolves with effervescence and production of coloured nitrous fumes in nitric-
acid, forming (as in the case of copper compounds generally) a green solution
which becomes intensely blue on addition of ammonia.
Brucite, MgO, H20, is easily distinguished from the other commonly
occurring minerals of this Table by its white streak, softness, pearly aspect,
and its magnesia-reaction, BB, with nitrate of cobalt. On ignition it evolves
30 to 31 per cent, water, and reacts alkaline.
\
[195]
TABLE XXIV.
[Lustre non-metallic. BB, slowly attacked or only in part dissolved by borax
or phosphor-salt. Infusible, or fusible on thinnest edges only. Hardness
sufficient to scratch ordinary window-glass distinctly. *]
A.— Insoluble (in powder) in hydrochloric acid.
Ai.— SPECIFIC GRAVITY OVER 5'0.
f With carb. soda and a little borax, BB, yielding metallic tin.
CASSITERITE (Tinstone): — Sn 78-62, 0 21-38, but most examples
contain traces of Fe203, Mn203, &c. Tetragonal (crystals often
twinned), see Note at end of Table; also massive and in rolled
pebbles ( = stream-tin, wood-tin) often with sub-fibrous structure.
Brown, black, grey, reddish, &c., rarely colourless; H 6-0-7-0; G
6-7-7-0. Infusible, but reducible on charcoal (especially if fused
with carb. soda, cyanide of potassium, or neutral oxalate of potash).
1 1 With carb. soda, BB, forming a slaggy mass or remaining
undissolved. Streak more or less distinctly coloured.
[This subsection includes only some comparatively rare species (essentially
Tantalates, Niobates, Nio-titanates) in which the lustre on the fractured sur-
face is distinctly sub-metallic, at least in typical examples. These species
belong properly, therefore, to Table X. When they occur in a fragmentary
form, or are indistinctly crystallized, their correct determination is not easily
effected. In most examples, traces of tin are obtained by the reduction process
with carb. soda and borax ; and by fusion in fine powder with bisulphate of
potash, all are more or less decomposed, the fused mass becoming blue when
warmed with a few drops of hydrochloric acid and a piece of tin or zinc.]
(BB, unchanged).
TANTALITE: FeO, Ta2O5, <fec.; Rhombic; black; H 6-0-6-5; G
6-3-8-0, usually 7-0-7-5.
* Minerals in which the normal degree of hardness scarcely exceeds 5-0 do not scratch glass
very distinctly ; and if slightly weathered or altered they may not scratch glass at all. To
avoid risk of error, therefore, infusible silicates of this character are placed both in the present
Table and in Table XXV. In trying the hardness of a mineral by a piece of glass, the* glass
should be laid flat on a table, and the mineral drawn with rather strong pressure sharply across
it — care, of course, being taken that no particles of quartz are attached to the substance.
Several species placed in this Table are not absolutely infusible when tested in the form of a
very fine splinter, although melting even then at the extreme point only, and requiring practice
on the part of the operator to effect this ; but, to avoid uncertainty in cases of this kind, the
species in question are referred to, again, in either Table XXVI. or Table XXVII.— the first
Containing fusible anhydrous silicates, and the latter, hydrated species.
196 BLOWPIPE PRACTICE.
COLUMBITE (Dianite): FeO, MnO, Nb2O5, Ta'Os, &c.; Rhombic;
black, generally somewhat iridescent; H 6-0; G 5-37-6-5. In fine
powder partially attacked by hot sulphuric acid.
MBNGITE: YO, CeO, ZrO2, TiO*, &c.; Eh.; black; H 5-5 ; G
5-4.8. Decomposed by hot sulphuric acid.
(BB, becoming yellow or pale- greyish and yielding a little water in the bulb-tube)
YTTHOTANTALITE: YO,ErO,FeO,Ta2Os, WO8, &c.; black, brownish,
yellow, often spotted; H 5*0-5-5; G 5-4-5-8.
FERGUSONITE ; POLYCRASE ; EUXENITE ; ^ESCHYNITE : — See TABLE
X., pages 126, 127.
(BB, partially fused or attacked on the surface or edges).
SAMARSKITB : YO, FeO, CeO, U2O3, Nb2O5, Ta2O*, &c.; Rhombic;
black; streak red-brown; H 5-0-6-0; G 5*6-5 '8. Decomposed in
powder by hot sulphuric acid.
A2. -SPECIFIC GRAVITY 3 -3-5-0.
f With carb. soda, ££, forming a slag only, or remaining undissolved,
(H = 10. In fine powder slowly combustible).
DIAMOND (Crystallized Carbon): — Reg., crystal-faces often curved
(see Note at end of Table). Colourless, pale yellowish or variously
tinted, sometimes black; lustre strongly adamantine; H 10; G
3-5-3-55, but in the black " carbonado " variety sometimes slightly
lower. BB, in fragments, unaltered per se and not attacked by the
fluxes, but in fine powder slowly combustible.
(BB, with Co-solution, APO* reaction).
CORUNDUM (Sapphire, Ruby, Adamantine Spar, Emery): Al 53-2f
O 46-8 ( - A12O3). Hexagonal (see Note at end of Table). H 9-0 ;
G 3-8-4-2, usually 3-9-4-0. Pink, blue, red, brownish, colourless,
dark-grey — the latter in the opaque variety Emery ; many crystals
colourless at one extremity, and blue or reddish at the other. BB,
quite infusible ; the powder fused with bisulphate of potash forms a
salt soluble in water. Ammonia throws down gelatinous APO*
(generally somewhat brownish from accompanying Fe20s) from the
solution.
DIASPORE: APO3 85, H20 15. Rhombic, but often in foliated
or scaly masses; H 6-6 -5 ; G 3-3-3-5. Colourless, white, brown7
violet, greenish, &c. In bulb-tube generally decrepitates, gives off
Crater, and falls into scaly particles. BB, like Corundum.
MINERAL TABLES : — XXIV. 197
TOPAZ : APO3, SiO2, Fl. Rhombic (see Note at end of Table) ;
H 8-0; G 3-5-3-57; yellow of various shades, pale bluish^green,
reddish-white, colourless ; cleavage very perfect, parallel with basal
plane. Infusible, but becomes colourless and loses polish on strong
ignition. BB, with fused phosphor-salt in open tube, gives fluorine
reaction. Pycnite and Physalite are columnar, opaque or semi-
opaque reddish-white or straw-yellow varieties.
CHRYSOBERYL (Cymophane): BeO 19-8, APO3 80-2; Rhombic
(see Note at end of Table); H 8-0-8-5; G 3-65-3-85; green of various
shades, greenish- white (often shewing a floating opalescence), and in
anany examples pale-red by transmitted light. BB, like Corundum.
SPINEL : Normally, MgO 28, APO3 72, but part of the MgO com-
monly replaced by FeO, and part of the APO3 by Fe2O3. Reg,
{crystals mostly small octahedrons, often twinned : see Note at end
of Table). H 8-0; G 3-5-4-1, usually about 3-55-3-6. Red, blue,
green, of various shades; reddish-white, black, rarely colourless.
BB infusible, but .many red varieties appear green whilst hot.
Decomposed in powder by fusion with bLsulphate of potash.
SAPPHIRINE: Essentially composed of MgO, FeO, APO3, SiO'.
Occurs in small granular masses in mica-slate from Greenland ; light-
blue, bluish or greenish-grey; H 7'5 ; G 3-42-3-47. Infusible.
CYANITE (Disthene) : APO8 62-10, SiO2 36-90. Anorthic, but
•chiefly in bladed or flat-fibrous masses ; H 7'0 on edges of crystals or
laminae, 5-5-5 on flat surfaces ; G 3-48-3-68. Bluish- white, light-blue,
grey, pale-green, reddish-white, tile-red. Infusible.
(Zn reaction by fusion in powder with mixture of carb. soda and borax
on charcoal)*
GAHNITE (Automolite) : ZnO 38*7, APO3 61-3, but small amounts
of MgO, MnO, FeO and Fe2O3 also frequently present. Reg. (crystals
mostly small octahedrons, commonly twinned as in Spinel) ; H 7 -5-8 0 ;
G 4-0-4-6 ; dark green, greenish-black. Dysluite is a manganese-
holding variety ; Kreittonite a ferruginous variety. BB, infusible ;
the powder fused with equal parts of earb. soda and borax gives a
.zinc sublimate.
(Fe reaction*).
PLEONASTE (Ceylanite) : Black or dark-green variety of SPINEL,
.see above, containing as a rule too much iron to give a distinct
•* A small particle, or some of -the powder, added to a bead of borax coloured by copper-
.-oxide, Quickly reduces part of the CuO to red CusO.
198 BLOWPIPE PRACTICE.
A1203 reaction with Go-solution. HERCINITE (mostly in small dull-
black granular masses) is still more ferruginous, practically all the
MgO being replaced by FeO. In these dark varieties the sp. gr. is
usually about 3*9 or 4-0.
STAUROLITE (Staurotide) : Composed essentially of FeO, MgO,
APO3, SiO2. Khombic : (crystals often cruciform twins, essentially
rhombic prisms, with V:Y near 129°, truncated on acute edges);
H 7-0-7-5; G 3-4-3-8; brownish-red, dark-brown. BB (as regards-
true Staurolite) infusible. In powder attacked by sulphuric acid.
See Note at end of Table.
(Chrome reaction : BB, with borax, emerald-green glass).
UWAROWITE (Ouvarovite, Chrome Garnet): CaO, APO3, Cr2O3,
SiO2. Reg. (crystals, small rhombic-dodecahedrons) ; H 7-5 ; G
3-4-3*53; bright green. Infusible.
(Sp. &r. 4-0-4-7).
ZIRCON (Hyacinth): ZrO2 67, SiO2 33. Tetrag. (crystals, com-
monly, eight-sided prisms with pyramidal termination) ; H 7*5 ; Gr
usually about 4*4; yellowish-brown, grey, light-brown, red, rarely
. greenish or colourless. Infusible. Slowly attacked by sulphuric
acid. See Note at .end of Table. Auerbachite, Ostranite, and
Malakon (Tachyaphalite), are probably slightly altered varieties, the
latter yielding 3 per cent, water. H about 6-5 ; G 3'9-4'l.
( Yielding water in bulb-tube).
OERSTEDITE: MgO, ZrO2, TiO2, SiO2, HSO (5-6 percent.). Tetrag. ;
H 5-5-6-0; G 3-63; red-brown, brownish-yellow, with adamantine
lustre. A rare, imperfectly-known species, allied to and resembling
Zircon.
MALAKON : An altered Zircon : see above.
f f With carb. soda, BB, dissolving more or less readily or forming en
fused glass.
(Titanium reaction).
KUTILE : TiO2. Tetragonal (crystals essentially prismatic, often
geniculated twins, sometimes acicular) ; H 6-0-6-5 ; G 4*2-4-3 ; red
(with strong adamantine, often sub-metallic, lustre), black (Nigrine,
mostly in rolled pebbles), yellowish-brown ; streak, pale-brown
BB, unchanged. Fused in fine powder with carb. soda (or better
with caustic soda or potash) forms a salt soluble in hydrochloric
MINERAL TABLES : — XXIV. 199
acid, the solution, slightly diluted and boiled with a piece of tin or
zinc, assuming a violet colour.
ANATASE or OCTAHEDRITE : TiO2. Tetrag. (crystals, small square-
based octahedrons or pyramids) ; H5'5-6'0; G 3 -8-4-0 ; indigo-blue,
brownish, yellowish-grey, with adamantine often sub-metallic, lustre.
BB, like Rutile.
BROOKITE : TiO2. Rhombic ? (V : V 99° 50' ; V : V 139° 55' ;
P:P in front 115° 43', at side 101° 35', crystals mostly tabular);
H 5-5-6-0 ; G 4-0-4-25 ; light-brown, yellowish, reddish, black in
Arkansite variety ; lustre adamantine to sub-metallic. BB, like
Rutile.
A3. -SPECIFIC GRAVITY UNDER 3 '3.
f With carb. soda, B&, forming a slag or semi-fused mass.
TOURMALINE (Light-coloured, red, green, and other infusiblo
varieties) : Essentially composed of MgO, A12O3, B2O3, SiO2, with
small amounts of Na20, Li2O, Fl, <fec. Hemi-Hexag. (crystals mostly
nine-sided prisms, longitudinally striated, with differently modified
summits : R : R about 133° 10', - 1 R 152° - 2 R 103° 3') ; green,
brown, red (Rubellite), blue (Indicolite), colourless;* H 7 -0-7 '5 :
G 2-9-3-2 ; pyro-electric. Infusible, or slightly attacked BB on thin
edges, as regards the varieties belonging to this Table. The powder
ignited in a platinum spoon and boiled with a few drops of sulphuric
acid, communicates a green tinge to the flame of alcohol or to the
point of the blowpipe-flame. In many varieties, also, the ignited
powder moistened with hydrochloric acid shews the red Li-line in
the spectroscope.
ANDALUSITE (Chiastolite) : A1203 63, SiO2 37. Rhombic (V : V
90° 50' - 91° 4') ; H, normally, 7-0-7 '5, but often lower from partial
alteration; G 3-10-3 -20 ; greyish-white, pearl-grey; pale violet, red,
reddish- white, greenish. BB, infusible ; with Co-solution, after
ignition, assumes a tine blue colour. CHIASTOLITE is a variety in
narrow straw-like crystals, or occasionally in thick prisms, imbedded
in clay slate, mica slate, &c., and presenting on the transverse section
a dark cross or black lozenge-shaped figure arising from a symmetrical
arrangement of the rock-substance in the centre and at the angles of
the hollow prismatic crystal.
* The black opaque varieties known as Schorl, and many brown varieties are easily fusible,
See TABLE XXVI.
200 BLOWPIPE PRACTICE.
SILLIMANITE: APO3 36-9, SiO2 63-1. Rhombic in crystn., but
commonly in fibrous or bladed examples ; H, normally, 6-7 ; G
3 '2-3-3; pale brown, yellowish-grey, greenish. BB, like Andalusite
and Cyanite, these three minerals being identical in composition and
closely related in other respects. Fibrolite, Bucholzite, Xenolite,
Monrolite, and Wcerthite, are varieties.
IOLITE (Dichroite, Cordierite) : MgO, FeO, APO3, SiO2, with
usually traces of MnO, and frequently (from alteration) a small
amount of H2O. Rhombic (mostly in short stout crystals of pseudo-
hexagonal aspect, with Y:Y 119° 10'), but commonly in granular
examples; H, normally, 7 '0-7 '5 ; G 2 -5-2 -7 ; blue, smoky-grey;
brownish or yellowish in certain directions by transmitted light.
BB, fusible with difficulty on thin edges ; with Co-solution becomes
bluish-grey or pale-blue.
ft With carb. soda BB forming a fused glass or bead.*
(Cleavage-planes more or less distinct).
EUCLASE: Essential composition: BeO, APO3, SiO2 (41-43 per
cent.), with a small percentage of water only driven off by intense
and prolonged heat, and therefore not detected in ordinary blowpipe
operations. Clino-Rhombic : (crystals much resembling the common
augite crystals,! small and brilliant) ; H 7'5 ; G 3'0-3'1 ; colourless,
pale-green, bluish-white. BB, in fine splinters, becomes opaque,
blisters slightly, and becomes rounded at the extreme 'point. With
carb. soda in proper proportion, forms an opaque pearl. A very rare
species.
BERYL (Emerald) : BeO 14-14, APO3 19-05, SiO2 66-84, with traces
of Fe2O3, and in the bright-green varieties (Emerald) a small amount
of Cr2O3. Hexagonal (crystals mostly six-sided prisms with large
basal plane); H 7-5-8-0; G 2-66-2-76; pale green, greenish-white,
emerald-green, occasionally pale yellow, bluish, or quite colourless.
BB, in fine splinters, becomes opaque white, and melts with difficulty
at the extreme point.
PHENAKITE: BeO 45-78, SiO' 54-22. Hex. or Hemi-Hex. ; H
7-5-8-0; G 2-9-3-0; colourless, pale yellowish. BB, infusible. With
* The flux should be added little by little. With too much, or too small a quantity, imperfect
results are obtained.
fBy atomic constitution, and also by crystallization, Euclase is regarded as related to
Datolite; but the actual composition and geological relations of these minerals are very
different.
MINERAL TABLES : — XXIV. * 201
small amount of carb. soda melts to a white bead ; with larger
quantity forms a slag. A very rare species.
ENSTATITE : MgO 40, SiO2 60, but with part of the MgO replaced
by small amount of FeO. Rhombic (V:V 91° 44' - 93°) ; mostly
in greenish- white, grey, or green cleavable masses; H 5'5 to nearly
6-0; G 3-10-3-29. BB, fusible on thinnest edges only. Bronzite,
commonly regarded as identical, is here kept distinct on account of
its inferior hardness. See TABLE XX Y.
ORTHOCLASE (Potash Feldspar) : K2O 16-9, APO3 18-4, SiO2 64-7.
Clino-Rh. (crystals often twinned: see Note to .TABLE XXVI.);
commonly in cleavable masses (the adjacent cleavage-planes meeting
at 90°) of a white, red, greyish, or light-green colour; H 6*0; G
2-5-2-6. BB, fusible with difficulty or on the edges only, but a fine
splinter is readily vitrified at the point. Red K-line clearly visible
in spectroscope if the powder be ignited and then moistened with
hydrochloric acid, or fused with carb. soda.
ALBITE (Soda Feldspar): Essentially, Na2O 11-8, AK)3 19-6,
SiO2 68 6. Anorthic (crystals often twinned : see Note to TABLE
XXVI.) ; commonly in white, red, or other-coloured cleavable masses,
with adjacent cleavage-planes meeting at 93° 36' and 86° 24', one
of these planes being generally striated. H 6-0 ; G 2 58-2-64. BB,
(in fine splinters) difficultly fusible, tinging the flame-border strongly
yellow.*
TRITOMITE : Normally, pure SiO2, but differing from quartz (although
belonging to the same System of Crystallization) by the character of
its crystals, the indications of cleavage which it shews in one direction,
its somewhat lower sp. gr., and its solubility in a saturated, boiling
solution of carb. soda. H 7*0 ; G 2-28-2-33 ; colourless, opaque
white. The crystals are mostly tabular from predominance of the
basal plane (practically unknown in quartz), or in fan-shaped or
other twins.
ASMANNITE : Normally SiO2, but differing essentially from quartz
and tritomite by its Rhombic crystallization, closely identical with
that of Brookite. H 5-5 ; G 2-245-2-247. Recognized by Maskelyne
* These feldspars are referred to in the present Table, because they are commonly regarded
as infusible by students who have had but little practice with the blowpipe, or who persist in
testing fragments of too large a bulk. They are described again in their proper place, with
Anoitbite and other distinctly fusible feldspars, in TABLE XXVI.
202 BLOWPIPE PRACTICE.
(in small cleavable grains with indications of rhombic crystallization)
in the meteoric iron of Breitenbach in Bohemia.
(No observable cleavage planes).
QUARTZ (Rock crystal, Amethyst, Calcedony, Agate, <fcc.) : Normally,
pure silica; Si 46 -67, O 53-33, but often coloured by traces of Fe203,
Mn2O, &c. Hexagonal or Hemi-Hexagonal (see Note at end of
Table) ; crystals, commonly six-sided prisms striated transversely
and terminated by a six-sided pyramid ; often massive, botryoidal,
granular; H 7'0 ; G 2-5-2-8 (clear examples and crystals commonly
about 2-65); colourless, white, violet, smoky-brown, pink, red, green,
grey, black, &c., the colours of massive examples often in stripes or
spots : see Note at close of Table. BB unchanged. With carb. soda
fusible with effervescence (due to expulsion of CO2) into a clear glass.
OPAL (Hyalite, &c.): SiO2, with from 2 to 20 per cent. H2O : the
latter usually 3-10 per cent. Opaque and strongly coloured varieties
also contain intermixed Fe203and other impurities. Uncrystalline, and
thus normally without action on polarized light. In nodular, botry-
oidal, and other massive examples ; H (normally) 5-5-6-5 ; G 1-5-2-5,
commonly 1-9-2-2; colourless, bluish-white, yellowish-red, with in-
ternal play of colours or iridescence (Noble Opal, Girasol, Fire-Opal) ;
also colourless, forming vitreous coatings or botryoidal masses 011
lava (Hyalite) ; or white, yellow, brown, red, bluish-grey, &c., often
in stripes or patches in the same specimen, and with more or less
waxy or sub-resinous lustre (Common Opal, Semi-Opal, Wood Opal,
&c.). BB usually decrepitates ; in the bulb-tube yields a little water;
otherwise like quartz. In powder, soluble in hot solution of caustic
potash. Jasper Opal is an opaque red, dull-yellow or brown variety,
mixed with a considerable amount of Fe2O3 or Fe203, H2O. Menilite
is a light-brown or bluish-grey variety in flat nodular pieces. Pearl-
sinter, Siliceous Sinter, Geyserite, &c., are stalactitic, encrusting or
porous varieties, deposited by many hot springs. Tripoli, Polishing
Earth, Raiidanite, are forms of amorphous silica, made up of minute
tests or coverings of diatoms.
MINERAL TABLES :— XXIV. 203
B.— Readily decomposed or dissolved (in powder) by hot
hydrochloric acid.*
Bi.- YIELDING NO WATER (OR TRACES ONLY) BY IGNITION IN BULB-TUBE.
f Decomposed, without gelatinization, by hydrochloric acid.
LEUCITE: K20 21-53, APO 23-50, SiO2 54-97, but part of the
K2O commonly replaced by Na2O. Tetrag., but crystals closely
resembling a trapezohedron of the Regular System. H 5'5-6'0; G
2-45-2-50 ; white, light-grey, yellowish or reddish- white. Only found
in crystals or small rounded masses in certain lavas. Infusible ; with
Co-solution, BB, assumes a bright blue colour. In fine powder,
•decomposed by hydrochloric acid, with separation of granular silica.
Shews red K-line distinctly in spectroscope when ignited and fused
with carb. soda or moistened with hydrochloric acid.
POLLUX : Cs'O, Na2O, A12O3, SiO2, with about 2J per cent. H2O,
the latter easily escaping detection in the examination of small
fragments. Reg. (crystals very minute combinations of cube and
trapezohedron 2-2). Commonly in small camphor-like colourless,
masses. H 5-5-6-5; G 2-8-2-9. Fusible only on thin edges. The
powder heated with fluoride of ammonium and then moistened with
hydrochloric acid shews in the spectroscope the two characteristic
Ccesium lines. These are bright blue and close together, one being
almost in the position of the blue Sr-line. A rare species, hitherto
only found in the Island of Elba.
f f Decomposed, with separation of gelatinous silica, by
hydrochloric acid.
(Zn reaction : characteristic ring-deposit on charcoal by fusion of test-substance
with carb. soda).
WILLEMITE : ZnO 73, SiO2 27. Hemi-Hex. (crystals commonly
six-sided prisms terminated by an obtuse rhombohedron of 128° 30',
but very small, and often with rounded edges); H 5*5; G 3-9-4-2 ;
white, brownish, red, green, <kc. Infusible, or attacked, BB, on
thinnest edges only.
(Zn and Mn reactions).
TROOSTITE : Like Willemite in composition but with part of the
* Reduce a small fragment (5 or 6 grains, or less) of the test-substance to powder ; place this
(by means of a folded slip of glazed paper) at the bottom of a clean test-tube ; twist a rolled -
up piece of soft paper round the top of the tube to serve as a handle, the ends of the paper
being twisted together; cover the powder to the depth of about half-an-inch with strong
hydrochloric acid, and boil gently (letting the flame touch the side of the tube near the top of
the acid) for two or three minutes.
204 BLOWPIPE PRACTICE.
JZiiO replaced by MnO and FeO. Hemi-Hex. (crystals comparatively
large, mostly six-sided prisms with rhombohedral terminations).
Commonly opaque or semi-opaque, yellowish-grey, greenish or brown.
BB with carb. soda forms a turquoise- enamel. Otherwise like
Willemite. Properly, a manganese variety of the latter species.
(Fl reaction with sulphuric acid).
CHONDRODITE : MgO, FeO, SiO2 (33-37 per cent.), MgFP. Clino-
Rh., but commonly in small granular masses of a yellow, yellowish-
white, reddish, brown, or green colour imbedded in cryst. limestone :
H 6-0-6-5 ; G- 3-0-3-25. BB infusible, or rounded only on thinnest
edges. CLINO-HUMITE is closely related. •
HUMITE : a Chondrodite of Rhombic crystallization. In small
crystals with numerous pyramidal planes, and generally a well-
developed basal plane, chiefly from Monte Somma, but recognized
also by E. Dana (with Chondrodite and Clino-Humite) from Brewster,
N.Y.
(No Zn or Fl reaction. G 3'0 to 3 -5).
CHRYSOLITE or OLIVINE (Peridot): Average composition, MgO 49,
FeO 10, SiO2 41 ; but in some varieties the FeO is higher, and MnO
and TiO2 are occasionally present. Rhombic, but often in small
granular masses in basalt, &c. H 6 -5-7-0 ; G 3-2-3-5. Green of
various shades, yellow, brownish, rarely yellowish-red. BB, infusible,
except as regards some very ferruginous varieties (Hyalosiderite, &c.)
which yield a magnetic slag or globule : see TABLE XXVI. Forsterite
(Boltonite) is identical in composition, crystallization and other charac-
ters. Hortonolite and Glingite are ferruginous varieties.
MONTICELLITE (Batrachite) : Average composition, CaO 35, MgO
22, FeO 5-5, SiO2 37-5. Rh. ; H 5-5; G 3-12; colourless, greyish,
pale greenish or yellowish-grey. BB, rounded on thinnest edges
only. Ignited and then moistened with HC1 acid, shews in spectro-
scope momentary red and green Ca-lines.
GEHLENITE : Essential composition, CaO, A1203, SiO2 with small
amounts of MgO, FeO, Fe'O3, and H2O; Tetrag. (crystals chiefly
simple square prisms) ; H 5-5-6-0; G 2-98-3-10; pale greenish-grey,
green, brownish. BB, rounded on thin edges. In spectroscope (after
ignition and moistening with HC1) shews Ca-lines very distinctly.
(G 4 or higher ; colour, black).
GADOLINITE : YO, CeO, BeO, FeO, SiO2, with traces of H2O, and
occasionally small amounts of ErO, CaO, &c. Rhombic or Clino-Rh.,
MINERAL TABLES : — XXIV.
hut chiefly in small granular masses without distinct cleava^^-i'p^ac^ V^ v
greenish-black; streak greenish-grey ;. H 6-5-7 '0; G 4-0-4-3, BB,
many varieties emit a peculiar glow, and most examples swell up
slightly and become greenish-grey, but none exhibit fusion, properly
so-called.
B2.— YIELDING WATER ON IGNITION.*
( BB, strong Cu-reaction with borax, or when moistened with hydrochloric acid) „
DIOPTASE : CuO 50-44, SiO2 38-12, H2O 11-44. Hemi-Hexagonal
(crystals chiefly combinations of hexag. prism and rhombohedron,
with angle of 95° 2Sr over polar edges of the latter) ; cleavage rhom-
bohedral, with R : R 1 25° 54r; bright emerald-green, with paler streak ;
H 5fO-5-5; G 3-27-3-35. BB, generally decrepitates, blackens, but
remains unftised. With carb. soda, on charcoal, gives metallic copper.
Gelatinizes in hydrochloric acid. A rare species. The amorphous
capper silicate, Chrysocolla, has normally a low degree of hardness,
and is decomposed by hydrochloric acid without gelatinization. See
TABLE XXY.
(BB, with carb. soda on charcoal, zinc reaction).
CALAMINE : ZnO 67-5, SiO2 25, H2O 7-5. Rhombic (crystals hemi-
morphic, i.e., with different terminations, but generally small, and
somewhat indistinct); H 5*0; G 3-3-3'5; colourless, or variously
tinted. The crystals pyro-electric. Frequently in botryoidal and
other massive examples. BB, infusible ; commonly decrepitates.
Decomposed with gelatinization by hydrochloric acid.
(No reactions of Cu or Zn. G 4 '9 to 5'0).
CERITE : CeO, SiO2, H2O (6-12 per cent.), but with part of the
CeO constantly replaced by LaO, DiO, CaO, &c. Hexag. (?); mostly
in massive examples of a red, reddish-grey, or brownish colour ; H
5-5 ; G 4-9-5-0. Gelatinizes in hydrochloric acid. The solution (if
not too acid) gives with oxalic acid a white precipitate which becomes
converted into tile-red Ce20* by ignition in the platinum spoon (Yon
Kobell).
(G under 3'0),
POLLUX : Yields on ignition a very small amount of water. Mostly
in small colourless camphor-like masses. See under B1, above.
* The minerals of this section belong properlj to Table XXV., as they scratch glass- more or
less indistinctly, but to avoid risk of error in their determination they are referred to also
here.
206 BLOWPIPE PRACTICE.
NOTE ON TABLE XXIV.
This Table includes a series of hard, infusible or very difficultly fusible
minerals of vitreous or other non-metallic lustre ; with, in addition, a few
species in which the lustre is occasionally sub-metallic. These latter are
comparatively rare, and they belong normally to Table X.
The following are the only species of importance, or of ordinary occurrence,
which possess sufficient hardness to scratch glass distinctly :— (1) The Dia-
mond; (2) a group of closely allied Tetragonal species, comprising: Cassiterite,
Rutile, Anatase, Zircon ; (3) the purely or essentially aluminous species,
Corundum, Chrysoberyl, Spinel, Gahnite ; (4) the purely siliceous species,
Quartz and Opal ; and, (5), the silicates, Topaz, Beryl, Cyanite, Andalusite,
Staurolite, Chrysolite, Chondrodite, Tourmaline, lolite, Leucite, Orthoclase,
Albite. »
The Diamond is distinguished essentially by its extreme hardness, its peculiar
adamantine lustre, and, in ordinary examples, by its crystallization. The
latter is Regular, but the crystals have almost invariably curved planes.
The principal forms comprise the tetrahedron and octahedron, and the
adamantoid 3'1'f, the last often distorted both by curvature of faces and by
elongation. The cleavage is octahedral. In the Bunsen flame on platinum
foil, diamond dust burns slowly away, but small splinters remain unchanged.
The Tetragonal species, Cassiterite, Rutile and Anatase, have the common
formula RO2 ; and with these, from its close correspondence in crystallization
with Rutile, the Zircon may be placed. Cassiterite, SnO2, is readily distin-
guished by its high sp. gr. (67-7'0), and by yielding reduced tin, BB, with
carb. soda or other reducing flux on charcoal. The crystals are commonly
short eight-sided prisms, terminated by the planes of the two corresponding
square pyramids (without basal plane); and they are_very frequently in
geniculated twins. P : P over polar edge = 121° 40' ; P : P = 133° 30'. In
mineral veins, Cassiterite is very generally associated with Wolfram and
Quartz, the latter forming the gangue or veinstone. The variety known as
"stream tin" occurs in small rolled pebbles and grains in alluvial deposits.
"Wood tin" is also an uncrystallized variety of light or dark brown colour
and concentric-radiated structure. Rutile, TiO2, distinguished in ordinary
examples by its red or brown colour and adamantine lustre, closely resembles
Cassiterite in crystallization, and especially in its geniculated twin-forms ;
p : P = 123° 8' ; vertical planes, in general, longitudinally striated. Rutile
occurs also occasionally in acicular radiating crystals, traversing quartz ; and
in small dark pebbles (Nigrine). Anatase or Octahedrite, another form of
TiO2, is mostly in small pyramidal crystals of a greyish-brown or peculiar blue
colour, with adamantine, more or less sub-metallic lustre. The crystals com-
monly shew a consecutive series of several pyramids, but are sometimes tabular
from extension of the basal plane. The angle over middle edge in Pr=136° 36'
(over polar edge 97° 51') ; in | P, 79° 54' ; in i P, 53° 22' ; in f P, 39° 30'.
Both Anatase and Rutile, and the Rhombic species Brookite, after fusion in
fine powder with carb. soda, are dissolved by hydrochloric acid. The solution
assumes a deep violet colour if slightly diluted and boiled with metallic tin.
MINERAL TABLES : — XXIV. 207
Zircon, ZrO2, SiO2, occurs occasionally in small granular masses, but most
commonly in simple crystals of the Tetragonal System. These are frequently
small square prisms terminated by a square pyramid measuring 123° 20' over
polar edges, and 84° 20' over middle edges. The basal plane is always absent.
Other common crystals are eight-sided, from combination of the two square
prisms, and in many a second pyramid is subordinately present. Some crystals,
again, shew the planes of one or more octagonal pyramids, 3 P 3, 4 P 4, 5 P 5,
but these planes are usually quite narrow or of small size. Zircon is mostly
red or red-brown in colour, but sometimes pale yellowish-grey, orange-yellow,
greenish, or colourless. Its hardness (7 "5), and its high sp. gr. which averages
4 '4 or 4-5, and always exceeds 4'0, are salient characters. BB loses colour,
but is quite infusible. The powder is slowly taken up by borax, the saturated
glass becoming opaque when flamed.
Corundum, A1203, is distinguished by its great hardness (9'0), its high sp.
gr. (3 '8-4*2), hexagonal or hemi-hexagonal crystallization, and complete infusi-
bility ; and by the fine blue colour imparted to it by treatment, BB, with
cobalt solution. It occurs under three more or less distinct conditions : (1)
in small transparent or sub-transparent crystals of a blue, pink, red, or other
colour, or sometimes colourless, forming the sapphire, ruby, &c. , of jewellers,
according to the colour; (2) in coarser translucent or opaque crystals and
cleavable masses of a greyish-green, red, brown or other tint, forming the
variety known as Adamantine Spar ; and (3) in fine-granular masses of a grey
or dark bluish-grey or black colour, commercially known as Emery. The latter
variety is sometimes mixed with grains of magnetic iron ore. The Corundum
crystals are mostly small, pyramidal combinations, or six-sided prisms with
narrow pyramidal planes and large basal face, and are frequently ill-formed.
The cleavage is basal, and also rhombohedral, with R : R 86° 4'. Many crvstals
are parti -coloured, blue and white, &c. ; and in some (asteria sapphire), a six-
rayed opalesceuce is visible. The cleavage faces often shew a delicate striation.
For blowpipe reactions, see the Table.
Chrysoberyl, BeO, A1203 (or perhaps Be'O8, APO3), is a comparatively rare
species of a green or greenish -white colour, sometimes reddish by transmitted
light, and often shewing a pale-bluish opalescence — whence the name Cymo-
phane, by which this species is also known. The crystals are Rhombic com-
binations, and are frequently in pseudo-hexagonal stellate groups* — both simple
and compound crystals being generally more or less tabular from extension of
the front vertical form or macro-pinakoid V. The hardness of chrysoberyl
(8 '5) nearly equals that of corundum ; and its comparatively high sp. gr.
(3 7-3'8) is also distinctive.
* Compound stellate and hexagonal groupings are common among crystals of the Rhombic-
System (Chrysoberyl, Marcasite, Discrasite, Aragonite, Cerusite, &c.), and are occasionally
seen in CHno-Rhombic and Regular crystals (the latter in Camphor, &c.), but are apparently
unknown among minerals and chemical products of recognized Hexagonal crystallization. Th<-
beautiful snow-crystalg so common in Canadian -winters are thus most probably not tiulv
hexagonal, but compound Rhombic forms. See a brief communication by the writer in the
Canadian Journal, 1860.
-OS BLOWPIPE PRACTICE.
Spinel, normally MgO, APO3, is readily distinguished, in most examples, by
its occurrence in small octahedrons, commonly twinned, as well as by its great
hardness (8'0),- and its high specific gravity (3'5-4'l). The colour is usually
some shade of red, but colourless and other-coloured varieties are also known.
After fusion in fine powder with bisulphate of potash it is partially soluble in
water. Ammonia throws down flocculent A1203 from the solution.
Gahnite is properly a zinciferous spinel, commonly in small octahedrons,
both simple and twinned, of black or dark-green colour, with greenish-grey
streak. Combinations of the cube with the rhombic dodecahedron and several
trapezohedrons, are also known. The simple octahedral crystals resemble
generally those of magnetic iron ore, but from this species Gahnite is distin-
guished by its want of magnetism, its pale streak, lower sp. gr. and greater
hardness, as well as by the zinc sublimate which it yields when fused, in
powder, with a mixture of about equal parts of carb. soda and borax, on
charcoal.
Quartz, SiO2, is distinguished readily from the preceding minerals by its
much lower sp. gr., as this never exceeds 2 '7 or 2 '8. Also by fusing readily
with carb. soda, and forming with that reagent a clear glass. Its want of
distinct cleavage is also characteristic. When crystallized, it is almost in-
variably in six-sided pi'isms, streaked across and terminated by the planes of
a regular hexagonal pyramid, the basal plane being always absent. The
pyramid-planes ?are often very irregular in size and shape. The principal
angles are as follows : over polar edge, 133° 44'; over point of crystal, 76° 26';
on adjacent prism-plane, 141° 47'. If the pyramid be regarded as consisting of
two complementary rhombohedrons, R on R equals 94° 1 5'; and in many
crystals only three terminal planes of this kind are present ; or the six planes
differ alternately in size, so as to form two sets of three. Many crystals also
shew a small plane (£ [2 P 2] in Naumann's notation), usually rhombic or
rhomboidal in shape and often striated, on alternate angles of the prism-
pyramid. Although normally colourless, Quartz very commonly presents
various shades of violet, pink, red, yellow, green, brown, £c., and some rock-
varieties are dark-grey or black. The crystallized examples comprise Rock-
crystal, Amethyst, Cairngorm, Smoky Quartz, &c. Massive, crystalline, or
sub-crystalline varieties include Common Quartz, Rose Quartz, Prase, some
kinds of Jasper, &c. (many of these containing intermixed iron-oxide, chlorite,
actynolite, or other foreign matters) ; whilst the nodular, stalactitic, and
amygdaloidal examples, composed largely of amorphous silica, comprise Cal-
cedony, Carnelian, Cat's-Eye, Chrysoprase (coloured apple-green by NiO),
Agate, Flint, Blood-stone, and other varieties.
Opal consists of amorphous silica, and most, if not all, examples yield a
certain amount of water on ignition. It occurs only in nodular, amygdaloidal
or botryoidal masses, or in small veins, essentially in trappean or volcanic
rocks. Its sp. gr. rarely exceeds 2'0 or 2 '2, and its degree of hardness is
always below that of ordinary quartz. In powder, it is dissolved more or less
readily by a hot solution of caustic potash or soda. The noble opal is beautifully
iridescent ; but ordinary varieties, comprising the so-called semi-opals, milk-
MINERAL TABLES : — XXIV. 209
opals, wood-opals, &c., much resemble calcedonic varieties of quartz, and are
usually opaque-white, brown, red, yellow, or grey in colour. Hyalite is a
transparent glassy variety in small botryoidal masses on lava. As regards
these and other varieties of Opal (see the Table), the more distinctive characters
are as follows: low sp. gr. (r5-2'5); amorphous structure; infusibility ;
presence of water ; solubility (or partial solubility if mixed with quartz) in
caustic potash.
Topaz is apparently an aluminous silicate combined with a fluoride. It con-
tains 17£ per cent, of fluorine, but gives a very feeble indication of that substance
with sulphuric acid, owing to its general insolubility. If fused, however, with
some previously fused phosphor-salt in a piece of open tube — the flame being
directed into the tube upon the assay — the glass becomes corroded. Topaz
occurs commonly in crystals, more rarely in small rolled pebbles (distinguished
from quartz pebbles by their ready cleavage and higher sp. gr. ), and occasionally
in opaque, granular or columnar masses (Pycnite, Physalite) of a reddish- white
or yellowish colour. In all, the hardness exceeds that of quartz, and the sp.
gr. is comparatively high (3 '5-3*6). The crystals belong to the Rhombic
System, and are invariably prismatic in aspect, with V : V 124° 17', and
V2:V293°ir. They are of three general types: (1), the Brazilian type,
essentially of a wine-yellow colour, presenting several vertical prisms (some
of which, however, are merely denoted by vertical striae), terminated by
four planes of a rhombic pyramid measuring 141° over front polar edge, and
101° 40' over side edge, the basal plane wanting ; (2) the Siberian type, essen-
tially of a pale blueish-green colour, resembling that of ordinary beryls, and
consisting of vertical forms with two more or less largely developed side-polars
or brachydomes, 2 P, measuring 92° 42' over the summit — the basal plane
being either absent or of comparatively small size, and other planes, if present,
being also but slightly developed ; and (3) the Saxon type, of very pale-yellow
colour, or nearly colourless, characterized essentially by its largely-developed
basal plane, with polar planes (of several forms) subordinately present. These
definitions hold good in the main, but crystals of intermediate type occasionally
occur.
Beryl, a silicate of alumina and glucina, occurs only in crystals or crystalline
columnar aggregations. The species consists of two leading varieties, com-
prising the Beryl proper and the Emerald. In both, the crystals as a rule are
simple hexagonal prisms with largely-developed basal plane ; but in some the
basal edges or angles (or both) are replaced by a border of narrow pyramidal
planes ; and occasionally the vertical edges are replaced by the prism V2. In
Beryl the vertical planes are generally longitudinally striated by an oscillation
between the two prisms, and crystals are thus often rounded or rendered more
or less cylindrical. The colour is usually greenish-white or some pale shade
of green, greenish-blue or yellow, and crystals often occur of large size. In
the Emerald the prism-planes are generally smooth, and the colour is emerald-
green, derived from the presence of a very small amount of sesquioxide of
Chromium. In both varieties the hardness exceeds that of quartz, and the
average sp. gr. equals 2 '7. In the blowpipe-flame, fine splinters lose their
15
21(5 BLOWPIPE PRACTICE.
colour, become opaque, and vitrify at the extreme point ; but, practically, the;
mineral may be regarded as infusible.
Cyanite or Kyanite, also known as Disthene, occurs commonly in long,
bladed or broadly-fibrous aggregations of a mixed blue and white colour, but
occasionally of a red, grey or other tint, and also in examples of narrow-fibrous
structure. The flat surfaces are readily scratched by a knife, whilst the edges
scratch glass strongly. The Crystal- System is Anorthic, but crystals as a
rule are imperfectly formed. They consist of long narrow prisms, with indis-
tinct terminal planes in most examples. The blue- white colour, bladed
structure, perfect infusibility, and assumption of a blue colour by ignition
with nitrate of cobalt, are the leading distinctive characters. In examples
from St. Gothard, frequently seen in collections, Cyanite crystals in mica slate
are closely conjoined with long narrow prisms of dark-red Staurolite.
Andalusiteis identical with Cyanite in composition (A1203, SiO2), but presents
a very different aspect, and crystallizes in the Rhombic System. It is generally
in granular masses, or in rectangular prisms, of a peach-blossom red or greyish
eolour. The crystals are often large and coarsely formed. In blowpipe
characters, it resembles Cyanite.
Staurolite may in general be recognized easily by its dark-brown, brownish-
black, or dark-red colour, its very common cruciform crystallization, and its
infusibility. Simple crystals however are also of frequent occurrence. These
consist invariably of an obtuse rhombic prism, with V : V 129° 20', truncated
(sometimes deeply, sometimes very slightly) on the side or acute vertical
edges, so as to form a six-sided prism, and carrying generally, in addition, a
front-polar form, P, mostly of small size. The basal plane has generally a-
rough surface, and many crystals are rough and dull throughout. These
crystals occur very commonly in cruciform twins, in some of which the
crystals cross each other at right angles, and in others obliquely. The prism-
apgle V : V appears to vary from about 128° 4(X to 129° 30'. B : P averages
124° 30' to 125° 30'.
Chrysolite proper is commonly of a pale-yellow or yellowish -green colour j
but in the variety known as Olivine, the colour is dark-green, or brownish-
yellow, or occasionally red, and this variety occurs chiefly in small granular,
more or less transparent masses, imbedded in basalt and lava. Chrysolite,
proper, occurs in small crystals and crystalline grains, and is normally a pure
silicate of magnesia, whilst in Olivine, much of the MgO is replaced by FeO.
The crystals are Rhombic, and are mostly combinations of the vertical forms
V, V, V2r and V ; the polar forms P, P, and 2P ; and the base B, the latter
sometimes failing. V : V ' = 130P 2' ; V2: V2; 94° 2' ; P: P over front edge,
139° 54' ; over side edge, 85° 16' -T F: B, 128° 17' ; 2P : 2P, over B or summit,.
80° 53'. Both varieties are decomposed, in powder, by hydrochloric acid, and
also by sulphuric acid, the silica separating in (usually) a gelatinous condition.
Normal examples are infusible, but very ferruginous varieties (hyalosideriter
&c.) often vitrify on thin edges. The leading characters of Qlivine are its
MINERAL TABLES: — xxiv. 211
peculiar greenish-yellow or green colour, its occurrence in traps and lavas, its
general infusibility, and its gelatinization in acids.
Chondrodite, essentially a magnesian fluo-silicate, occurs commonly in the
form of small granular masses, chiefly of a yellow colour, imbedded in
crystalline limestone ; but green, yellowish-red, and other-coloured varieties
are also known. It occurs also, though less commonly, in small crystals with
numerous planes, belonging to the Clino-Rhombic System. Humite and Clino-
Humite (chiefly from Vesuvius) are closely similar in composition and general
physical characters, but the first is Rhombic in crystallization, and the latter
presents different angular values.' All give a marked fluorine reaction by
treatment in powder with hot sulphuric acid. For other characters, see the
Table.
Tourmaline may in general be recognized without difficulty by the essentially
triangular character of its crystals and crystalline needles, as seen more
especially on the transverse fracture. The crystals are generally nine-sided
V
prisms, consisting of three planes of a hemi-hexagonal prism g", combined with
the second hexagonal prism V2, the latter occurring as a bevelment on the
vertical edges of the half -form. These prisms, when perfect, are terminated
by rhombohedron-planes, with or without a basal plane, or frequently by
rhombohedron-planes at one extremity, and by a single large basal plane or
dissimilar forms at the other. The rhombohedron-planes belong chiefly to the
forms R, - £R, - 2R, in which the angle over polar edges equals, respectively,
133° 10' or thereabout, 155°, and 103°. Black varieties (known as Schorl) and
most dark-brown varieties are easily fusible (see TABLE XXVI.), but the red,
green, blue, clear-brown, and colourless examples are either infusible, or
fusible only on the thinnest edges. Some crystals are red internally and green
externally, or present different colours at the extremities ; and nearly all the
clear exainples are transparent when viewed across the prism, and opaque
longitudinally. All, moreover, exhibit electrical polarity when heated. *
lolite, known also as Dichroite and Cordierite, is commonly in the form of
small, granular, vitreous or resino-vitreous masses, imbedded in granitic and
crystalline metamorphic rocks ; but is found at some localities in distinct
crystals, and occasionally in the form of small rolled pebbles in alluvial deposits.
The colour is mostly dark-blue or pale-blue by reflected light, and brownish
or yellowish by transmitted light, whence the name Dichroite. Some varieties,
however, are colourless, grey, or blueish-brown. The crystals belong to the
Rhombic System, but have in general a pseudo-hexagonal aspect : a common
combination consisting of the forms V, V, P, P, and B ; with V: V 119° 1(X;
B : P 150° 49'. Fine splinters melt at the extreme point, but practically the
* This may be shewn by suspending a crystal from the ring of the blowpipe-lamp, or other
'•.onvenient support, by means of a piece of thin silk-thread tied round the centre of the crystal.
The latter is heated carefully in a small platinum or porcelain capsule, care being taken not to
burn the thread, over a spirit-flame or Bunsen-burner. On the capsule being removed, one
^.nd of the prism will be attracted, and the other end repelled, by a glass stirring-rod or stick
>f sealing-wax rubbed previously for a few seconds on the coat-sleeve.
212 BLOWPIPE PRACTICE.
species may be placed among the infusible silicates. From blue Corundum
(Sapphire), and from Sapphirine and blue Spinel, it is readily distinguished
by its low sp. gr. (2 "6). From blue Tourmaline (Indigolite), also, by lower
sp. gr., and by not becoming electric when heated ; and from Quartz, by
forming, BB with carb. soda, a slaggy semi-fused mass in place of a clear
glass. Many examples of lolite are partially altered or decomposed, and
these give traces of water in the bulb-tube.
Leucite is readily distinguished, as a rule, by its occurence in small rounded
grains or crystals of a white, grey, or pale-yellowish tint, in lava. The crystals
closely resemble the trapezohedron 2-2 of the Regular System, but have been
shewn by Von Eath to be really Tetragonal — at least as regards most
examples, if not all. Many crystals contain minute needles and scales of
augite, magnetite, &c., scattered through their substance. In powder, leucite
is slowly decomposed by hot hydrochloric acid. The solution, rendered pasty
by partial evaporation, shews the red K-line in the spectroscope if held 011 a
clean platinum wire for a few seconds in the outer edge of a Bunsen-flame.
The K-line is rendered visible also by igniting some of the powder on a loop
of platinum wire, and then dipping it into some carbonate of soda or powdered
fluor-spar, and again exposing to the flame. The glare from the sodium
spectrum may be entirely cut off by the intervention of a piece of deep-blue
glass.
Orthoclase-; Albite. These species belong properly to Table XXVI, and
their crystallographic and other characters are there described. In general,
they form cleavable masses of a white, flesh-red, bright-red, grey, pale-yellowish
or clear-green colour ; or occur in crystals of a more gr less flattened aspect,
often twinned (see Note to TABLE XXVI.). In Orthoclase the principal clea-
vage planes meet at right angles ; in Albite, at angles of 93° 36' and 86° 24',
and one of the cleavage planes in the latter species generally shews a delicate
striation, best seen under the magnifying glass. Orthoclase, treated in powder
with carb. soda (as described under Leucite, above) shews very distinctly the
red K-line in the spectroscope.*
* This test for the presence of potash in Orthoclase, so far at least as regards the use of carb.
soda, was first described by Bunsen. If the mineral, in powder, be fused with fluor-spar the
red K-line comes out, I find, still more distinctly ; and many examples, when thus treated,
shew the Li-line as well. By the intervention of a piece of blue glass the Ca-lines (from the
fluor-spar) and the Li-line become obliterated, and only the K-line remains visible. The latter
is also brought out in most if not in all cases by simply moistening the test-matter, after
ignition, with hydrochloric acid .
[213]
TABLE- XXV.
[Lustre non-metallic (in some cases pseudo-metallic). Slowly or incompletely
dissolved BB by phosphor-salt. Infusible, or fusible on thin edges only.
Hardness insufficient to scratch ordinary window-glass. |L V;i,*Vv
*?• v%yV- '
A. — Occurring in micaceous or foliated masses or crystals,
the foliae elastic or flexible, and easily separable by
the finger-nail.
Ai.— FOLLE DISTINCTLY ELASTIC.
MUSCOVITE (Potash Mica) : Essentially K2O 9, APO3 35, Si
with small amounts of Fe2O3, H20, Fluorine, &c. Rhombic or
Rhombic (?), but crystals hexagonal in aspect. Optically biaxial,
with large angle of divergence. Structure thin-foliated or scaly, the
folise easily separable. White, brown, black, green, &c., with metallic-
pearly lustre on cleavage-plane ; flexible and elastic in thin pieces ;
H 2-0-3-0; G 2-7-3-1. BB, exfoliates, and melts readily on the
edges (if in the form of a thin scale) into a greyish- white enamel.*
In acids, insoluble. Fuchsite is a more or less deep -green chromi-
ferous variety, in fine-scaly aggregations. Damourite and Margarodite
are hydrated micaceous minerals, apparently derived from Muscovite.
See TABLE XXV II. Roscoelite is a Vanadiu m-mica (in small greenish-
brown or green, radiately arranged foliae of metallic-pearly lustre)
from Eldorado Co., California.
PHLOGOPITE (Potassic-Magnesian Mica) : K2O 12-75, MgO 32-55,
APO3 13-95, SiO2 40-75, with small amounts of H20, F, &c. Rhombic
(optically biaxial), but essentially hexagonal in aspect ; thin-foliated,
or scaly ; chiefly yellowish-brown, with golden, metallic-pearly lustre
on cleavage-face; H 2 -5-3-0 ; G 2-75-2-90; BB, whitens, and melts
on thin edges into a greyish-white enamel. In powder decomposed
by sulphuric acid, the silica separating in colourless scales. Common
in crystalline limestones.!
BIOTITE (Potassic-Ferromagnesian Mica) : Closely resembles Phlo-
gopite in composition and general characters, but usually of dark
colour — green, black, or brown ; optically uniaxial, and of assumed
* The Micas (Muscovite, Phlogopite, Biotite and other representatives, Lepidolite excepted),
are always placed among the infmible species, in works on Determinative Mineralogy. As a
rule, however, all melt more or less readily on the edges when tested in the form of a thin
scale. In the spectroscope, all shew the red K-line, and many the Li-liue also, either per set
or when moistened, after ignition, with HC1 acid.
f This species is present iu great abundance in most of the apatite deposits of Canada.
214 BLOWPIPE PRACTICE.
Hexagonal crystallization. Fusible on edges into a black or dark
enamel. Decomposed by sulphuric acid. Commonly found in vol-
canic and trappean rocks, but many volcanic micas are optically
biaxial.
A3.— FOLLE FLEXIBLE BUT NOT ELASTIC.
f Yield water by ignition in bulb-tube.
CHLORITE (Pennine) : MgO 13 to 27, FeO 15 to 30, APO3 19 to
23, SiO2 25 to 28, H2O 9 to 12. Hexag. or Hemi-Hex. (crystals
mostly tabular), but commonly in foliated and scaly examples of a
dark or rich green colour ;' flexible in thin pieces; H 1'0-1'S; G
2-65-2-95. Fusible on thin edges into a yellowish-grey or dark and
often magnetic glass. Decomposed by sulphuric acid. Metachlorite,
Prochlorite, A phrosiderite and Tabergite, are closely related chloritic
substances-. The latter occurs in coarse, bluish-green, foliated masses.
K^EMMERERITE : A chromiferous chlorite of a red or violet-red
colour, or green by reflected, and red by transmitted light. Mostly
in hexagonal pyramids and prisms of foliated structure.
BIPIDOLITE (Clinochlore) : Clino-Rhoinbic in crystallization, but
identical in general characters and composition with Chlorite proper.
Epichlorite, Korundophyllite, Helminthite, are varieties or closely
related. Pyrosclerite is a chromiferous variety from Elba. Delessite
is an essentially ferruginous chlorite, allied to this or the preceding
species, of frequent occurrence in amygdaloidal traps.
PYROPHYLLITE (Foliated Kaolin) : APO3, SiO2, H2O, with traces
of MgO, &c. Essentially in radio- folia ted examples of a clear green
or greenish-white colour, and somewhat pearly lustre ; flexible in
thin pieces; H I'O; G 2-75-2-95. BB, exfoliates and curls up, but
remains unfused, or vitrifies slightly on thinnest edges only. With
Co-solution assumes a fine blue colour. Talcosite, from Victoria, ih
a closely related substance, passing into Kaolin proper.
f f No water -, or traces only, in bulb-tube.
TALC: Essential composition, MgO 31-7, SiO2 63-5, H2O 4-8, but
the H2O is not driven off by moderate ignition, and is thus regarded
as basic. Occurs commonly in six-sided tabular crystals and foliated
masses of a pearly-white, greenish- white, clear-green, or greenish-
grey colour. H TO; G 2-67-2 80. BB, exfoliates, becomes opaque-
white, and melts on thin edges, but less easily than mica. With
Co-solution, becomes pale-red. Insoluble in acids.
MINERAL TABLES I — XXV. 215
33, — Occurring in distinctly schistose or foliated examples, but
the component folise more or less brittle, not flexible.
Bi.— YIELD WATER BY IGNITION IN BULB-TUBE.*
MARGARITE (Pearl Mica) : CaO, APO3, SiO2, H2O, with small
amounts of K2O, Na2O, Li2O, MgO, F, &c. Rhombic (?) .; mostly in
six-sided tables and lamellar masses of a pearly-white, pale-green,
reddish or greyish colour; the lamellae more or less brittle. H
3-5-4-0; G 2-95-3-10. BB, melts on the edges, often with slight
intumescence. Scarcely attacked by acids. In spectroscope, after
ignition and moistening with HC1 acid, shews momentary red and
green Ga-lines, and, in most examples, red K and Li lines, also.
Emeryllite, Euphyllite, Diphanite and Gilbertite, are identical or
/closely related. Euphyllite, however, is decomposed by sulphuric acid.
ANTIGORITE (A slaty Serpentine) : MgO 36 to 37, FeO 6 to 7,
SiO2 41 to 43, H2O 11-5 to 12-5, with traces of APO3, &c. In
schistose masses of a dark green or greenish-brown colour; H 2*5 ;
G 2-62. Fusible on thin edges. Slowly decomposed by sulphuric
acid.
SCHILLER SPAR (Bastite). Probably an altered Bronzite : Con-
tains MgO, FeO, SiO2, with about 12 per cent. H2O, and small
amounts of K2O, CaO, Cr2O3, APO3, &c. In schistose or foliated
masses of a dark-green colour, with yellowish-brown reflections on
the cleavage surfaces. H 3-5-4-0; G 2'6-28; BB, melts on the
edges only; becomes brown and sometimes magnetic -after ignition.
Decomposed by sulphuric acid.
PICROPHYLL : A hydrated magnesian silicate occurring in sub-
foliated or coarse-fibrous examples of a greenish-grey colour; H 2 -5^
G 2-73. Fusible on thin edges. Regarded as an altered Pyroxene.
CHLOROPHYLLITE : Contains MgO, MnO, APO3, Fe2O3, SiO2, HX).
In foliated masses or coarse indistinctly formed crystals of a green
or brownish colour. H about 3'0 ; G about 2-7. Fusible on thin
«dges only. Scarcely attacked by aoids. Probably, in part, an
altered lolite.
GROPPITE: Contains K2O, CaO, MgO, APO3, Fe2O8, SiO2, H2O
{7 per cent.). In foliated or scaly masses of a rose- red or brownish-
* Few, if any, of the minerals belonging to this section can be regarded as true species. A>-
a rule, they consist of altered products of more or less unstable composition, and their deter-
jniuative characters are commonly ill-defined. This remark applies, with few exceptions, ti>
•the representatives of the present Table, generally.
216 BLOWPIPE PRACTICE.
red colour, the folise brittle; H 2-5-3-0; G 2-73. BB, whitens, and
vitrifies on thin edges.
B* — ANHYDROUS SPECIES : NO WATER, OR TRACES ONLY, EVOLVED IN
BULB-TUBE.
BRONZITE (Foliated Enstatite) : Contains MgO, EeO, SiO2. Com-
monly in schistose or foliated masses of a dark-brown or dark-green
colour, with pseudo-metallic bronze-like lustre, and very perfect
cleavage in one direction. H 4-0-5-0 ; G 2-9-3-5. Fusible on
thinnest edges only. Not attacked by acids.
ANTHOPHYLLITE : MgO 27-8, FeO 16-7, SiO2 55-5. Rhombic,
but essentially in thin-lamellar and fibrous masses, with tolerably
easy cleavage in three directions; yellowish-brown, greenish-grey,
bronze-green, with somewhat metallic-pearly lustre. H 5-0; G 3-2.
BB, vitrifies only on thinnest edges into a black magnetic enamel :
practically, infusible. Very slightly attacked by acids.*
CLINTONITE : Composed essentially of CaO, MgO, APO3, SiO2, with
traces of H2O. Chiefly in hexagonal tables of a brown or yellow
colour, with metallic-pearly lustre; H 5-0; G 3-0-3*2. Practically
infusible. Decomposed by hydrochloric acid. Xanthophyllite (in
yellow radiating lamellae on certain talcose schists), and Brandisite
(in dark-green tabular crystals, weathering brownish), are apparently
related compounds, but are only partially attacked by hydrochloric
acid. In Clintonite and in these related silicates the silica is under
20 or 21 per cent. Ignited and moistened with HC1 acid, all shew
in the spectroscope red and green Ca-lines in momentary flashes.
C. — Occurring in crystals or in granular, fibrous, compact, or
other non-micaceous examples. Streak-powder colour-
less, pale-green, or lightly- tinted,— not black.
CX— YIELDING WATER BY IGNITION IN BULB-TUBE.
f Form with borax, ££, a deeply coloured glass.
(Ou reaction)*
DIOPTASE : CuO 50-44, SiO' 38-12, H2O 11-44. In emerald-green
crystals — hexagonal prisms with rhombohedral summit-planes — suffi-
* In ordinary examples, Bronzite and Anthophyllite can rarely be separately distinguished.
The first is regarded as a Rhombic representative of the Pyroxene series, and the latter as a
Rhombic Amphibole ; but the characteristic pyroxene and amphibole angles (87° 6' and 124° 30%
or angles approaching these, are rarely determinable. Hypersthene is a very ferruginous and,
comparatively hard. Bronzite, distinctly fusible. See TABLE XXYI.
MINERAL TABLES : XXV. 217
ciently hard (5-0-5-5) to scratch glass slightly : See TABLE XXIY.
G 3-3. BB, decrepitates and blackens, but does not fuse. With
carb. soda, easily reduced. Gelatinizes in heated hydrochloric acid.
A rare species, in crystalline limestone from the Kirghis Steppes of
Western Siberia.
CHRYSOCOLLA (including Kupferblau, &c.) : Composition somewhat
variable, but essentially CuO 45-27, SiO2 34-21, H2O 20-52. In
amorphous and botryoidal masses, coatings on copper ores, and
occasionally in pseudomorphs. Colour, green, greenish-blue, bright-
blue; brownish or black from presence of Fe2O3, MnO2, <fec.; H
2-0-5-0; G 2-0-2-6. BB, blackens, but does not fuse. On charcoal
with carb. soda, reduced to metallic Cu. Decomposed with separation
of silica (but as a rule without perfect gelatinization) by hydrochloric
acid. Demidowite is a Chrysocolla mixed with copper phosphate.
Asperolite a variety with 27 per cent. H2O. Other varieties are
mixed with copper carbonate, opalized silica, <fec.
ALLOPHANE (Cupreous varieties) : A1203, SiO2, H20 (35 to 36 per
cent.), mixed with copper silicate. In amorphous, stalactitic and
botryoidal examples, coatings, &c., of a light-blue, green, red, or
brownish-yellow colour. H about 3-0 ; G about 2-0. BB, blackens,
and often swells up slightly, but does not fuse. In HC1 acid,
gelatinizes.
(Ni reaction: page 43).
RJETTISITE: NiO, SiO*, H2O (11 per cent.), mixed with Fe20»,
copper-phosphate, cobalt-arseniate, <fec. Amorphous, incrusting;
green of various shades; H 2-0-2-5 ; G 2-3-2-4.
GENTHITE (Nickel-Gymnite) : NiO, MgO, SiO2, H2O (19 per cent.).
In green and greenish-yellow coatings on some examples of Chromic
Iron Ore, and occasionally in soft sub-earthy masses. H 2*0-4-0;
G about 2-4. BB, infusible, blackens.
PIMELITE: MgO, NiO, A1203, SiO2, H2O (21 per cent.). In
earthy masses, coatings, &c., of an apple-green colour. H 1-0-2-5 ;
G 2-3 (to 2-71). BB, blackens, and vitrifies on thin edges. Alipite
and Chrysoprase-Earth are identical or closely related compounds.
(Fe reaction).
ANTHOPHYLLITE : In yellowish-brown, or greenish metallic-pearly
examples of lamellar or fibrous structure. Some examples only yield
traces of water on ignition, See B2, above.
218 BLOWPIPE PRACTICE.
HISINGERITE (Thraulite) : FeO, Fe203, SiO2, H2O (10 to 20 or 22
per cent.), with small amounts of MgO, APO3, &c. In earthy and
nodular masses of a pitch-black or brownish-black colour, with
brownish streak. H 3-0-4-0; G 2 -6-3-1. BB, becomes magnetic,
and vitrifies on the edges, or in some examples melts into a steel-grey
magnetic globule* (see TABLE XXVII.). Decomposed by HC1 acid
with separation of slimy silica.
NONTRONITE : Essential components Fe203, SiO2, H2O (2 1 to 2f>
per cent.), but small amounts of APO3, CaO, &c., are also generally
present. In earthy and nodular masses of a yellow, green, greenish-
white or brownish colour; H 1 -0-1-5; G 2-0-2-4. BB, infusible, or
fusible on the edges only, but becomes magnetic. Pinguite and
Gramenite are identical or closely related. Chloropal (Unghwarite)
is also very similar in general characters and composition, but is
somewhat harder, probably from admixture with opalized SiO2.
(Or reaction: see page 48).
WOLCHONSKOITE : Cr2O3, Fe2O , SiO2,- H2O (about 20 or 21 per-
cent.), with small amounts of MgO, MnO, APO3, &c. In earthy
and nodular masses of a grass-green or blackish-green colour ; H
1-5-2-5; G 2-2-2-3. BB, practically infusible; gelatinizing in HC1
acid.
MILOSCHIN (Serbian) : APO3, Ci^O3 (under 4 per cent.), SiO2, IPO
(about 23 per cent.). In blue or blue-green, earthy and amorphous
masses; H 1 -0-2-0; G 2-1-2-2; adheres to the tongue. BB, infusible.
Partially decomposed by hydrochloric acid.
f f Form BB with borax an uncoloured or lightly-tinted glass.
(The saturated borax-glass becomes opaque-white on cooling or when flamtd).
CERITE: CeO (LaO, DiO) 73-5, SiO2 20-4, H2O 6-1. Chiefly in
fine-granular masses of a red, brownish, or reddish-grey colour. H
5-0-5-5 (scratches glass feebly) ; G 4-9-5-0. BB, becomes dull yellow,
but remains unfused. Gelatinizes in hydrochloric acid.
THORITE : ThO2, SiO2. H2O. Heg. ? Mostly in small black masses,
often fissured, and sometimes with reddish coating ; streak, brownish
or reddish; H about 4-5; G 4-4-4'7. BB, becomes yellow, but
* L. H. Fischer: Clavis der Silicate: 1864. This work, a Determinative Grouping of the
Silicates (containing many original observations), should have been referred to among the list
of works oh Determinative Mineralogy at page 21.
MINERAL TABLES :— XXV. 219
remains unfused. Gelatinizes in HC1 acid. Very rare : commonly
regarded as altered Orangite.
ORANGITE: ThO2, SiO2, H2O. Tetragonal? Mostly in small
granular or sub-foliated examples of a. reddish-yellow or orange-red
colour; H 4-5; G 5 -2-5 -4. Gelatinizes in HC1 acid. Very rare;
accompanies Thorite in the micaceous zircon-holding syenite of
Brevig in Norway.
[NOTE. — Most examples of Cerite, Thorite, and Orangite, when ignited and
moistened with hydrochloric acid, shew a momentary Ca-spectrum.]
(A zinc-sublimate formed on charcoal by fusion with carb. soda and borax).
CALAMINE : ZnO 67 -5, SiO2 25, H2O 7'5. Crystallization Rhombic ;
crystals mostly hemimorphic (with B plane at one extremity only),
arranged in drusy or fan-shaped aggregations, and generally flattened
o
from extension of the side vertical or brachy-pinakoid faces V. The
species occurs also very commonly in botryoidal, cavernous, and
other examples ; colourless, white, yellowish, brown, green, light-
blue ; H 5'0 (scratches glass feebly); G 3*3-3'5 ; crystals, pyro-
electric. Infusible, BB, or vitrified slightly on thinnest edges, only,
only. Gelatinizes with hydrochloric acid. Ignited with Co-solution,
becomes green (or partly blue and partly green) on cooling.
(Slowly attacked BB by borax ; the glass not rendered opaque by flaming.
With Co-solution, assume a distinct blue colour).
KAOLIN: APO3 397, SiO2 46-4, H2O 13-9. Chiefly in earthy or
fine -granular masses made up in part of microscopic scales. White,
pale-red, greenish- vvhite ; H 1-0 or less; G 2 -1-2-3 (or in some
varieties slightly higher: 2-3-2-6). Infusible; decomposed by hot
sulphuric acid. Cimolite, Anauxite, Pelicanite, Hunterite, &c., are
related aluminous compounds, but contain a somewhat higher per-
centage of silica.
NACRITE or PHOLERITE : A crystalline or sub-foliated Kaolin, in
pearly-white scaly masses or six-sided tables, often in fan-shaped
groups. Composition and other characters as in Kaolin proper.
AGALMATOLITE (Figure Stone * in part) : K2O, APO3, SiO2, H20
(about 5 per cent.). White, pale-grey, yellowish, pale-red, green,
* Although many of the smaller Chinese images are carved out of this stone, a great number
(perhaps the greater number) consist of steatite or of serpentine. In these, the substance
blackens in the bulb?tube, and assumes a flesh-red colour after ignition \vith Co-solution.
220 BLOWPIPE PRACTICE.
greenish-white ; mostly in fine-granular almost compact masses, but
these consist frequently of microscopic scales; H 2-0-3-0; G 2-8-2-9.
BB, whitens, and vitrifies on thin edges. Decomposed by sulphuric
acid. Shews the red K-line very distinctly in spectroscope, when
ignited and moistened with HC1 acid.
FINITE : K2O, MgO, FeO, Fe2O3, APO3, SiO2, H20 (4 to 8 per
cent.). In six-sided and twelve-sided, more or less opaque crystals,
of a greyish-white, grey, brown, greenish or bluish colour ; H 2-0-3-5 ;
G 2 -5-2 -9. BB, vitrifies on thin edges only. In spectroscope shews
distinctly the red K-line when ignited and moistened with hydro-
chloric acid. Apparently an altered lolite. The following sub-
stances, all of which give a K-spectrum, are more or less closely
related: Pyrargillite from Finland (brown, brownish -red, H2O 15-5
per cent.) ; Fahlunite (dark-brown, dark-green, greyish, H20 8 to 9
per cent.); Weissite (grey, brown, H2O 3 to 5 per cent.); Iberite
from the vicinity of Toledo (greyish-green, in coarse six-sided prisms,
aq. .5 to 6 per cent.); GIESECKITE (greenish-grey, aq. about 6 per
cent.) ; Liebenerite (green, greyish, aq. about 5 per cent.). The two
latter are regarded as altered nepheline ; the others as altered iolite.
In all, the hardness is below 4-0, and the sp. gr. below 2-9. Gigan-
tolite belongs to the same series, but is readily fusible (see TABLE
XXVII).
ESMARKITE: MgO, MnO, FeO, Fe20», A12O3, SiO2, H2O (5-5 per
cent.). This mineral, like those placed under Finite, above, is also
apparently an altered lolite; but it is placed here, apart, as the
representative of a non-potassic series. Occurs mostly in coarse
twelve-sided prisms of more or less scaly texture; grey, brown,
greenish, &c., in colour; and dull and opaque, or practically so. H
3-0-4*0; G 2-6-2*8; fusible on thin edges only. Praseolite, Aspasio-
lite, and JBonsdorffite, are identical or closely related substances of a
green or greenish-brown colour, occurring mostly in six-sided, eight-
sided, or twelve-sided prisms, with dull surface and rounded edges.
HALLOYSITE: A12O3 35, SiO2 41, H2O 24. Nodular, earthy;
greenish or greyish-white, pale dingy blue; H 1-0-2-5; G 1-9-2-1 ;
feels somewhat greasy, and adheres to the tongue. Infusible. Decom-
posed by hot sulphuric acid. Lenzinite and Glagerite are identical or
closely related. Kollyrite is also very similar in general characters,
but contains 40 per cent. H2O, with 46 APO3, and only 14 SiO2.
MINERAL TABLES I — XXV. 221
(Assume a pale-red colour after ignition with Co-solution, or do not become blue.
In the bulb-tube, generally blacken).
STEATITE (compact or fine-granular Talc) : White, greenish, &c.,
often mottled. More or less soapy-feeling and very sectile. On
ignition, yields traces of water only. See C2, below.
SERPENTINE: MgO 43-48, SiO2 43-48, H2O 13-04; but part of
the MgO very generally replaced by FeO, and small amounts of
NiO, APO3, and Cr2Os, are occasionally present. In fine-granular or
compact masses, or occasionally slaty or fibrous. Sometimes, also, in
pseudomorphs after Olivine, Pyroxene, Spinel, and other species.
Of various colours, but chiefly some shade of green, greenish- or
greyish-yellow, brown, or red, two or more colours in irregular
patches being often present in the same specimen; translucent or
opaque; H 3-0-4-0; sectile; G 2-5-2-7. BB, whitens, and fuses on
thin edges. Deeply-coloured (ferruginous) varieties do not redden
distinctly with Co-solution. Decomposed by sulphuric, and also,
though less easily, by hydrochloric acid. Picrolite, Picrosmine,
Bowenite, Tletinalite, Marmolite, Antigorite (see above, B1), Chrysotile
(see below), and many so-called Soapstones, are varieties,
CHRYSOTILE (Serpentine-Asbestus) : Properly, a fibrous asbestiform
serpentine, in silky, easily separable fibres, of a yellowish, greenish-
white, or oil-green colour. BB, a fine fibre melts at the extreme
point. Baltimorite is a bluish, coarsely fibrous variety, often con-
taining APO3 and Cr203. Metaxite is also a fibrous serpentine.
MEERSCHAUM (Sepiolite) : MgO, SiO2, H2O (the latter somewhat
variable, but usually 11 or 12 per cent.). In fine-granular, more or
less compact and very sectile masses of a white, pale-yellow or
greyish colour. Sometimes in pseudomorphs after Calcite, &c. H
1-5-2-5; G about 1-0-1-3. BB, hardens, and melts on thin edges.
Decomposed by HC1 acid, with separation of slimy silica.
DEWEYLITE (Gymnite) : MgO 37, SiO2 41, H2O 22. In more or
less compact masses of a dingy yellow or yellowish-white colour and
somewhat waxy lustre; H 2-0-3-0; G 1-9-2-22. BB, fuses only on
the thinnest edges. Decomposed, without gelatinization, by hydro-
chloric acid. Kerolite is closely related in general characters and
composition.
YILLARSITE : MgO, FeO, MnO, SiO2, H2O. In pyramidal or thick
tabular crystals (apparently rhombic, and probably pseudomorphous
MRS BLOWPIPE PRACTICE.
after Olivine), arranged generally in compound groups ; also in
rounded granular masses; green, dingy-yellow, or greyish; H 3'0 ;
G 2-9-3-0. Infusible. Decomposed by acids.
PYRALLOLITE: MgO, CaO, A1203; SiO2, H20. Commonly in
prismatic, coarse-fibrous, or granular masses, rarely in Clino-Rhombic
crystals with basal cleavage ; green, greenish-white, pale yellowish-
grey ; H 3-0-4-0; G 2-53-2-73. Fusible on thin edges only. Gener-
ally regarded as an altered Pyroxene.
C2.— YIELD NO WATER (OR TRACES ONLY) BY IGNITION IN BULB-TUBE.
f Sectile.
( With Co-solution assume a flesh-red colour).
STEATITE (compact or fine-granular Talc): MgO 31*7, SiO2 63-5,
H2O 4-8 — but the latter is only evolved on intense ignition. Massive :
fine-granular or compact; also in pseudomorphs after Scapolite,
Orthoclase, Andalusite, Spinel, Pyroxene, and other species ; white,
grey, greenish, reddish, &c., often mottled; H 1-5-2-5; very sectile ;
G 2-6-2-8; more or less soapy-feeling. BB, hardens considerably,
and fuses on thin edges. Decomposed by hot sulphuric acid.
f f Not sectile.
(Forming zinc- sublimate on charcoal by fusion with carb. soda and borax).
WILLEMITE: ZnX) 73, SiO2 27.. Hemi-Hex. (crystals small, fre-
quently with rounded edges, mostly hexag. prisms terminated by a
rhombohedron. measuring 1^8° 30' over a polar edge*) ; white, green,
brownish, reddish, &c. ; H 5'5 (scratches glass feebly); G 3'9-4-2.
BB, infusible, or vitrified here and there on surface only.f With
Co-solution becomes green, or green and blue. Gelatinizes with
hydrochloric acid.
TROOSTITE (Manganesian Willemite) : Like Willemite in general
composition, but with part of the ZnO replaced by MnO and FeO.
Commonly in opaque or semi-opaque yellowish -grey or brown crystals
like those of Willemite, but comparatively large. BB, with carb.
soda, strong Mn-reaction. Gelatinizes with HC1 acid.
* This rhombohedron is commonly regarded as the form f R. In the form R, the angle over
a polar edge equals 116° ; and in the form — £ R, also often present (especially in the manganese
variety Troostite), it equals 143° 24'.
t A small splinter scarcely becomes rounded or changes form, but if examined by the
magnifying glass after exposure to the blowpipe, its surface exhibits points of vitrification.
MINERAL TABLES: — XXV.
{Forming with borax, BB, a glass which becomes opaque on flaming. Moistened
with sulphuric acid, tinges the flame-point pale-green},
XENOTIME: YO, CeO, P205. See under the Phosphates, TABLE
XVII., page 164. This rare species is referred to here, as from its
general insolubility in acids and its slow solution BB in phosphor-
salt, it might escape detection as a phosphate.
(Slowly attacked, BB, by borax, the bead remaining clear when flamed).
CHIASTOLITE : Properly a variety of Andalusite, but of lower
degree of hardness (5'0-5'5) from incipient alteration. Occurs in
slender straw-like prisms, or occasionally in thicker crystals, imbedded
chiefly in clay-slate or mica-slate, and presenting on the transverse
section a dark cross, or a black lozenge at centre and angles. See
TABLE XXIV., page 199.
ANTHOPHYLLITE : In yellowish-brown, greenish-grey, or bronze--
green, lamellar or fibrous masses; H 5-0-5-5; G 3 '2. BB, vitrifies
on thinnest edges only, into a black magnetic enamel. The borax-
ijlass, coloured by iron. See under B2, above,
D. — Streak-powder, black or greyish-black.
This subdivision includes merely varieties of ANTHRACITE in which
the lustre is more or less non-metallic. When pure, Anthracite con-
sists essentially of carbon, but usually contains a small percentage of
H, N, and O, besides intermixed mineral matter or so-called "ask"
H 2-5-3-25 ; G 1-2-1-8. BB, in splinters practically unchanged, but
in fine powder burns gradually away. In the bulb-tube generally
yields a small amount of water. Not attacked by the fluxes. In-
soluble in acids and caustic alcalies-.
NOTE ON TABLE XXV.
The minerals which belong properly to this Table comprise a series of
infusible or difficultly fusible silicates of low or comparatively low degree of
hardness, many yielding to the finger-nail, and all being readily scratched by
the point of a knife. Whilst some of these silicates are definite species, pre-
senting a fixed composition and well defined physical characters, others are
mere mixtures, or more or less unstable products of decomposition. The
latter in many cases can only be distinguished from one another by complete
chemical analysis ; and, as a rule, no two examples of these pseudo-species,
unless obtained from absolutely the same spot, will be found to agree exactly
224 BLOWPIPE PRACTICE.
in the amount of water or other components. False species of this unstable
and indefinite character are easily made by any one capable of performing an
ordinary mineral analysis, but their acceptance leads to much confusion, and
should therefore be rigorously disallowed. In Tables of the present character,
however, products of this kind, already recognized in mineralogical systems
and text-books, could not be altogether ignored. By a little latitude, the
greater number might be placed under two conventional species : the first
including all hydrated magnesian or alumino-magnesian products of the kind
in question ; and the second, all the purely or essentially aluminous matters
of this kind.
The more common representatives of the Table belong to the following
groups : — Micas, Chlorites, Talcs and Steatites, Serpentines, Kaolins, Pinites,
Copper Silicates, Zinc Silicates.
The micas are especially characterized by their metallic pearly or general
pseudo-metallic lustre, and their ready cleavage into thin, elastic leaves.
Those of the present Table include the three species, Muscovite, Phlogopite,
and Biotite — the two latter essentially magnesian species. Muscovite, com-
monly called Potash Mica, although the other species contain an equal or
even greater amount of potash, is chiefly distinguished by its want of solu-
bility in sulphuric acid, whilst the other two species, when in fine powder,
are decomposed in the boiling acid, with separation of fine scales of silica.
Phlogopite is generally of a golden-brown colour ; Biotite, dark-green or black.
The optical characters of these micas are also different. Muscovite is biaxial,
with angle of divergence 44°-78° ; Phlogopite is also biaxial, but with smaller
divergent angle (under 20°, sometimes under 5°) ; and Biotite is (normally)
uniaxial. In thin scales, all melt without difficulty on the edges into an
opaque- white or greyish enamel ; and when moistened, after ignition, with
hydrochloric acid, all shew in the spectroscope the red K-line, with in some
cases the Li-line also. Some examples shew one or both of these spectra by
simple insertion per se in the flame. Red and green Ca-lines sometimes
appear from intermixed calcite. Muscovite is commonly present in granites,
gneiss and mica slate, as one of the essential components ; Phlogopite is
chiefly found in the bands of crystalline limestone associated with many
gneissoid rocks ; and Biotite occurs most generally, though not exclusively,
in lavas, trachytes, and basalts.
The Chlorites are chiefly distinguished by their dark-green colour and foli-
ated structure ; their flexibility in thin leaves (without the elasticity of the
micas); their softness; and the marked amount of water (about 12 p. c. )
which they yield by ignition in the bulb-tube. Some chlorites, however,
especially chromiferous examples, present a deep-red colour. In thin scales,
all fuse more or less readily on the edges into a greyish or black enamel, the
latter often magnetic. The original Chlorite has been split up into several
species, more or less distinct. The principal comprise Chlorite proper or
Pennine (the Ripidolite of Gustav Rose) characterized by its hexagonal or
rhombohedral crystallization ; and the clino-rhombic species, Clinochlore or
Ripidolite (of von Kobell), for which the old name of Chlorite was retained
MINERAL TABLES : — XXV. 225
by Rose. These species closely resemble one another, and in ordinary, un-
crystallized examples they can scarcely be distinguished. As a rule, however,
Chlorite is a more ferruginous species, and thus generally becomes magnetic
after fusion or strong ignition, and its sp. gr. is in some examples as high as
2-9 ; whilst that of Ripidolite rarely exceeds 2'7. This distinction, however,
only applies in special cases, and is practically of little value.
The Talcs and Steatites are exclusively or essentially magnesian silicates,
containing 4 or 5 p. c. of apparently basic water, only expelled by intense
ignition. Hence, by 'ordinary ignition in the bulb-tube, these minerals yield,
as a rule, merely traces of moisture, and they are thus generally placed among
anhydrous species in determinative groupings. The formula may be written
(H20, 3 MgO), 4 SiO2. Talc proper is easily recognized by its occurrence in
soft, flexible, more or less pearly scales and foliated masses of a white, clear-
green or other light colour, combined with its soapy feel, and its property of
assuming a flesh-red tint by ignition with cobalt-solution, the latter character
serving to distinguish it from pyrophyllite and other foliated minerals of the
aluminous Kaolin group. Although very soft and flexible, the folise are
inelastic. Steatite is a more or less compact Talc, usually white, grey,
greenish, reddish, or mottled in colour, and very sectile. It usually gives
distinct traces of water on ignition, and, like ordinary talc, it hardens greatly
and becomes vitrified on thin edges in the blowpipe flame. Sub-slaty vari-
eties, forming a transition into Talc proper, occasionally occur.
The Serpentine group is closely related to that of the Talcs and Steatites,
its included species being essentially hydrated magnesian silicates, compara-
tively soft and sectile ; but (unlike the Talcs) all yield a distinct amount of
water on moderate ignition. The group is chiefly represented by Serpentine
proper ; the asbestiform variety or sub-species of the latter, known as Chry-
sotile ; the foliated or schistose varieties or sub-species, Antigorite, Schiller
Spar,. &c. ; and the related magnesian silicates, Meerschaum, Deweylite or
Uymnite, Kerolite, and other similar compounds. Most of these are decom-
position products of more or less unstable character. In the Serpentines, the
amount of water averages 12 per cent., but in Deweylite and in many
Meerschaums it exceeds 20 per cent., and is still higher in Kerolite. Serpen-
tine proper is commonly in beds or masses of fine-granular or occasionally
sub- slaty structure, and of dark-green, yellow, brown, red, or other colour,
two or more tints or shades of colour frequently occurring in the same speci-
men. The so-called "Noble Serpentine " is more or less translucent and of
rich shades of colour ; whilst "Common Serpentine" is opaque or translucent
on the edges only, and comparatively dull or muddy in colour. Mixtures of
serpentine with calcite or dolomite are known as Ophiolite, Verde Antique, or
Serpentine-marble. Serpentine is unknown in true crystals, but frequently
occurs in pseudomorphs (essentially pseudoinorphs of alteration) derived from
Oliviiie, Pyroxene, Spinel, and other magnesian species.
The Kaolins present a remarkable resemblance in outward characters to
many Talcs and Steatites, some representatives of the group (Pyrophyllite,
&c.) being made up of soft, flexible, pearly, and foliated masses, whilst others
16
226 BLOWPIPE PRACTICE.
are fine-granular (or microscopically scaly) in structure, and more or less soapy
to the touch. But the Kaolins are essentially aluminous, and thus assume a
distinct blue colour after ignition with cobalt-solution. The principal repre-
sentatives of the group comprise Kaolin proper, Nacrite or Pholerite, Pyro-
phyllite, Agalmatolite, Halloysite, and Kollyrite. These are sufficiently
described in the Table. All are essentially decomposition products.
The Finite group consists of crystallized pseudomorphous products derived
from the alteration of lolite, or apparently in some cases from that of Nephe-
line or other species. .These substances are chiefly in six-sided or twelve-
sided prisms, often more or less ill-formed, with dull lustre, and dingy- white,
pale-grey, greyish-green, dull-blue, reddish, or dark-brown colour. The hard-
ness is under 4'0 (usually 2 -5-3*5), and the sp. gr. about 2 '6 or 2*8. They
may be grouped conveniently under three series, typified respectively by
Finite, Esmarkite and Gigantolite. The minerals referrible to Finite and
Esmark.ite are fusible on the edges only ; those referred to Gigantolite melt
before the blowpipe more or less readily. These latter, therefore, come under
notice in Table XXVII. In the Finite series, a certain amount of potash is
always present (although that alkali has not been found in the supposed
parent-stock, lolite), and the included forms (Finite, Weissite, Fahlunite,
Pyrargillite, Iberite, &c.) shew very distinctly the red K-line in the spectro-
scope, after being ignited and then moistened with hydrochloric acid, or by
fusion with carbonate of soda or fluor-spar. The yellow Na-line, and the
green and red Ca-lines from the fluor-spar, may be entirely cut off by the
intervention of a piece of deep-blue glass. The representatives of the Esmar-
kite series, on the other hand (including Esmarkite, Bonsdorfnte, Praseolite.
Aspasiolite, &c.), do not contain potash.
The group of Copper Silicates includes the rare Dioptase and the compara-
tively common Chrysocolla, the latter including in the Table both the green
and blue varieties. The characters of these are sufficiently given in the text.
The amorphous Chrysocolla, as a rule, will alone come under the student's
observation.
The Zinc Silicates, which include the anhydrous Willemite, with its man-
ganese-holding variety, Troostite, and the hydrous species Calamine, are also
described in sufficient detail in the Table. They find a place also in Table
XXIV. , as in most examples they are sufficiently hard to scratch glass slightly.
They do not readily yield a zinc sublimate on charcoal, unless fused in powder
with a mixture of carb. soda and borax, or treated according to the method
recommended at page 39. With cobalt-solution they assume partly a green
and partly a blue colour, the latter, more especially, after strong ignition.
[227]
TABLE XXVI.
[Lustre non-metallic (in some cases pseudo-metallic). Slowly or incompletely
dissolved, BB, by phosphor-salt. More or less readily fusible. Yielding
no water (or merely traces) on ignition].
A. — Fusible into a black or very dark bead, magnetic or
non- magnetic.*
Ai.— OCCURRING IN SCALY, MICACEOUS, OR ASBESTIFORM EXAMPLES.
f Scaly or micaceous. Readily decomposed by hydrochloric acid.
LEPIDOMELANE : K2O 9-20, FeO 1243, APO3 11-60, Fe2O3 27-66,
SiO2 37*40, with traces of H2O, &c. In hexagonal tables and scaly
masses of a black colour with greenish streak, the scales somewhat
brittle ; H 2'5-3'0 ; G 3-0-3-2. BB forms a black magnetic glass or
enamel.
ASTROPHYLLITE : K'O, Na2O, CaO, MgO, MnO, FeO, Fe2O3, A12O3,
SiO2, with 7-66 per cent. TiO2 and a little H2O, according to Pisani's
analysis. In six-sided tables and micaceous prisms of a bronze-yellow
colour and metallic-pearly lustre. Folise slightly elastic. BB easily
fusible with some bubbling into a black, more or less magnetic bead.
The HC1 solution, slightly diluted and boiled with a piece of tin,
assumes an amethystine colour.
w% In the spectroscope both Lepidomelane and Astrophyllite, when moist-
tened, after ignition, with HC1 acid, shew the red K-line.
f f Readily decomposed by sulphuric acid. Structure micaceous.
BIOTITE (Potassic Ferro-magnesian Mica) : Mostly in dark-green
or black micaceous examples, with flexible folise. Fusible on the
edges only : See TABLE XXV.
f t f Fibrous. Insoluble in acids.
BYSSOLITE (Ferruginous, asbestiform Amphibole) : In fibrous
masses of a green or greenish-brown colour. BB, fuses into a black
and often magnetic bead.
A«. —OCCURRING IN CRYSTALLIZED, LAMELLAR, GHANULAR, OR OTHER NON-
MICACEOUS EXAMPLES.
f Easily decomposed, with gelatinization, by hydrochloric acid.
(Fusion-Jbead magnetic.)
FAYALITE : FeO 70-6, SiO2 29-4, but part of the Fe in some
examples replaced by Mn \ intermixed FeS or FeS2 also frequently
* The silicates of this Division form also in most cases a black glass by fusion with carb.
soda.
228 BLOWPIPE PRACTICE:
present. In black or greenish-black masses, commonly magnetic?
from intermixed pyrrhotine or magnetite; H 6 '0-6 -5; G 4'0-4'2,
BB, easily fusible into a black magnetic bead.
HYALOSIDERITE (Ferruginous Chrysolite): MgO, FeO, SiO3. In
small prismatic crystals of the Rhombic System, yellowish-brown in
colour; H 6-0-6-5 ; G 3-4-3*5 ; BB, fusible only in fine splinters into
a black more or less magnetic slag.
ILVAITE or LIEVRITE : CaO 13-7, FeO 35-2, Fe*O3 19-6, SiO2 29-3
(with 2-2 basic water1?). Rhombic; crystals essentially prismatic,,
with V:V 112° 38', and V2 : V2 106° 15', the Y planes in most
crystals longitudinally striated ; also in coarsely fibrous, columnar,
and granular masses ; black, brownish-black, with dark streak ; H
5-5-6-0; G 3-8-4-1. Easily fusible into a black magnetic bead.
Moistened with HC1 acid, shews red and green Ca-lines in spectro-
scope very distinctly.
ORTHITE or ALLANITE (Cerine): CaO, CeO, LaO, FeO, FeW,
APO3, SiO2, with, in some examples, YO, MgO, H2O, &c. Clino-
Rhombic : crystals in general transversely elongated, but sometimes
tabular ; occurs also in columnar and fine granular examples, mostly
of a pitch-black colour and somewhat sub-metallic aspect ; but also
brown or dull greyish-yellow, and then more or less resinous in lustre ;
H 5-5-6-0; G 2-8-3-8 or 4-0. BB melts easily, with bubbling, into
a dark, generally magnetic, bead. Bodenite, Bagrationite, Erdmaii-
nite, and Muromontite, are probably varieties.
ALLOCHROITE (Ferro-calcareous Garnet) : CaO, FeO, SiO2. Chiefly
in rhombic dodecahedrons of a dark -red, dark -green, or brown colour.
Easily fusible. Decomposed, with gelatinization, by hydrochloric
acid in some examples, only. See under Garnet, below, page 230.
SIDEROMELANE : CaO, Fe203, A1203, SiO2, with small amounts of
MgO, MnO, K2O, NaO. In black amorphous masses resembling
black Obsidian; H 6-0; G 2-55-2-60. Easily fusible into a black
magnetic slag. Practically identical with Tachylite, but distinguished
by its larger amount of iron, and by dissolving somewhat less readily
in hydrochloric acid.
(Fusion-globule not magnetic. No sulphur-reaction.}
TACHYLITE : CaO, FeO, A12O3, SiO2, with, in general, small amounts
of K2O and Na2O, MnO, MgO, and sometimes TiO2. In black or
brownish-black amorphous masses of vitreous lustre, much resembling
MINERAL TABLES : — XXVI. 229
some Obsidians. H 6-0-6-5 ; G 2-51-2-60. BB, easily fusible with
bubbling into a black (non-magnetic) glass or enamel. In spec-
troscope, shews Ca-lines, and in many examples the red K-line also.
An essentially volcanic or trappean product.
TEPHROITE : MnO 70-3, SiO2 29 -7> In granular, cleavable masses
of a reddish-grey or dull reddish-brown colour, weathering brownish-
black : the cleavage rectangular. H 5'5-6'0; G 4-0-4-12. Easily
fusible to a black slag. With carb. soda gives strong manganese-
reaction. Knebelite is probably identical, although said to be in-
fusible.* Tephroite differs essentially from the more common man-
ganese silicate Rhodonite, by its ready gelatinization in HC1 acid.
Rhodonite being practically insoluble.
{fusion-product not magnetic. Strong sulphur •-reaction.-]')
HELYINE : BeO, MnO, FeO, SiO2 with Mn, Fe, S. Reg.; crystals
chiefly tetrahedral ; occurs also, though rarely, in botryoidal masses ;
H 5-5-6-5; G 3-2-3-4; yellow, brownish, yellowish-green. BB, in
O.F. a dark bead, dull yellow in R.F. In hydrochloric acid, evolves
odour of sulph, hydrogen, and is1 decomposed with gelatinization.
DANALITE : A flesh-red or yellowish-grey Helvine, with MnO
largely replaced by ZnO. Crystallizes in regular octahedrons, some-
times with truncated edges, and occurs also in small, disseminated
grains. Blowpipe and acid reactions like those of Helvine proper,
but a zinc-sublimate formed (with carb. soda and borax) on charcoal
t f Decomposed imperfectly by hydrochloric acid, but completely by
sulphuric acid.
SPHENE (Titanite1): OaO (partly replaced by FeO and MnO) 28'57,
TiO2 40-82, SiO2 30'61. Clino-Rh.; crystals mostly small, with more
or less ortho-rhombic aspect, often tabular and frequently twinned :
see Note at end of Table ; brown, grey, yellow, green, &c. ; occurs
also in cleavable and fine-granular masses ; dark-brown, light-brown,
grey, yellow, green, &c.; H 5-0-5-5 ; G 3'4-3'6 ; lustre vitreo-resinous.
BB, commonly becomes yellow and melts with bubbling to a dark
^enamel. The sulphuric acid solution (or the aqueous solution obtained
by fusing the finely ground mineral with bisulphate of potash)
* Judging from its stated characters and composition, its infnsibility is most improbable.
I have tried without success to procure a specimen for comparison.
t See page 61, Experiment 1. The carb. soda should be used somewhat in excess. These
,:uinerals give also a strong Mn-reaction.
230 BLOWPIPE PRACTICE.
assumes a violet colour if boiled with a few drops of hydrochloric
acid and a piece of tin*. In spectroscope, shews red and green Ca-lines
if moistened with HC1 acid after strong ignition.
KEILHAUITE (Yttro-titanite) : CaO, YO, APO3, Fe203, TiO2, SiO2,
Commonly in dark reddish-brown twin-crystals resembling those of
Sphene, but often of comparatively large size ; H 6-0-7-0 ; G 3*5-3 -72..
BB, like Sphene.
SCHORLAMITE (Ferro-titanite) : CaO 29-38, Fe2O3 20-11, TiO2 21-34,
SiO2 26-09, with small amounts of MgO, FeO^ and alkalies. Keg.;
crystals rare, commonly the Rhombic Dodecahedron, or that form
with the trapezohedron 2-2, hence much resembling garnet crystals.
Occurs mostly in small granular masses of a pitch-black colour ; H
7-0-7-5 ; G 3-78-3-86. BB, fuses on the edges, or entirely, into a
black slag or bead ; other reactions like those given under Sphene.
\
f f f Partially or slightly attacked in normal condition by hydrochloric-
acid, but readily decomposed by that acid after fusion, f
(During fusion, impart a red colour to the flame.}
FERRUGINOUS LEPIDOLITE : In brown, grey, or greyish-red scaly
aggregations; H 2-5; G 2-9-3-0. BB, fusible with great bubbling into-
a dark magnetic bead. See Lepidolite proper, under B2., page 234.
(During fusion, impart a green colour to the point of the flame.)
AXINITE : CaO 20'2, MnO 2-6, FeO 2-8, Fe2O3 6-8, APO3 16-3;
B2O3 5-61, SiO2 43-5, with small amounts of MgO, K2O, and basic
H'2O. Anorthic ; crystals essentially flat or very thin rhornboidal
prisms, replaced only on single edges and angles ; brown, violet-brown^
green, pearl-grey, amethystine, different tints often shewing in dif-
ferent directions; H G'5-7'0; G 3-27-3-33. BB, easily fusible, with
green coloration of the flame-point, to a black bead, which generally
becomes green and translucent in the inner flame.
(No green or red coloration of flame, during fusion* Never in fibrous, acicular,.
or prismatic examples. )
GARNET : Dark sub-species ( Almandine, Aplome, Andradite, Pyrope,.
Melanite, Spessartine, &c.): Average composition, RO 33 to 43, R?O:v
* In fine powder, Sphene ig also sufficiently decomposed by hydrochloric acid to give this
characteristic reaction when the solution is boiled with a piece of metallic tin.
t The fused bead or slag must be crushed under paper on the anvil, or in a small steel mortar^
and then ground to a fine powder*
MINERAL TABLES : XXVI. 231
21 to 32, SiO2 35 to 40 (RO = CaO, MgO, FeO, MnO ; R2O3 - A120»
1VOS). Reg.; principal forms, the rhombic dodecahedron and the
trapezohedron 2-2 (see Note at end of Table). Frequently in rounded
grains and indistinct crystals; red, brown, black, dark-green, &c. ;
H 6-5-7-5 ; G 3-6-4-3 (in dark varieties). * BB, fusible more or less
readily into a dark and generally magnetic bead. The Bohemian
garnet, Pyrope, which occurs chiefly in small grains of a deep-red
colour, contains a small amount of chromium (CrO ?), and becomes
black and opaque on gentle ignition, but recovers its red colour and
translucency on cooling. As shewn by Dr. L. H. Fischer, it is only
decomposed to a slight extent, after fusion, by hydrochloric acid.
(Essentially in fibrous, acicular, or prismatic examples.)
EPIDOTE (Pistacite, Thallite, Bucklandite, Piedmontite, Withamite,
«fec.): CaO 36 to 40, APO3 18 to 30, Fe203 7 to 20 or Mn2O3 10 to 25,
SiO2 36 to 40, with traces of MgO, &c., and about 2 per cent, basic
water. Clino-Rh. ; crystals in general elongated parallel to the
ortho-axis, with cleavage planes meeting at angle of 115° 24': see
Note at end of Table ; occurs also in acicular, fibrous, and other
examples ; green of various shades, greenish-yellow, black. (In man-
ganese varieties, blackish-red or dull cherry-red.) H 6'0-7'0; G 3'3-3'5.
BB, swells up, and forms a dark cauliflower-like slag, or in some
cases a black glass, generally magnetic. In phosphor-salt, somewhat
easily decomposed, differing remarkably in this respect from examples
of Pyroxene and Amphibole of similar aspect.
t f t f Very slightly attacked by hydrochloric acid, both before and
after fusion.
(In triangular or nine-sided prisms; or in acicular, columnar, or fibrous ex-
amples, triangular on cross-fracture. )
SCHORL ; BLACK or DARK-BROWN TOURMALINE : Approximate
composition : MgO 7 or 8, FeO 5 to 10, A1203 30, B2O3 9 or 10,
SiO2 38, with small amounts of K2O, Na2O, Li20, KaO, MnO, F, and
basic water. Henri-Hexagonal (see Note at end of Table) ; also very
commonly in columnar and fibrous masses, the component fibres
shewing under the magnifying glass a triangular cross section ; Black,
dark-brown, with vitreous external lustre ; H 7-0-7*5 ; G 3*03-3-20 ;:
pyro-electric. BB, melts more or less easily to a black slag or glas.%
which often attracts the magnet. The fused bead reduced to fine
powder is decomposed by strong sulphuric acid, Alcohol added to
232 BLOWPIPE PRACTICE.
the solution, and ignited, burns with the green flame characteristic
of B2O3. The crushed bead made into a paste with sulphuric acid,
imparts this colour to the blowpipe-flame. A drop of glycerine in-
tensifies the reaction : see page 28.
in lamellar or foliated masses with strongly pronounced
one direction.)
HYPERSTHENE (Ferruginous Bronzite) : MgO, FeO, SiO2. Rhombic,
but crystals of quite exceptional occurrence ; essentially in bronze-
brown, green, or greenish-black, lamellar masses, with metallic-pearly
lustre on cleavage plane; H 5-0-6-0; G 3-3-3-4. BB, fusible more
or less easily into a black magnetic bead or slag. See under Bronzite
in Table XXV.
(In lamellar or fibrous masses or distinct crystals, with cleavage-angle and prin-
cipal prism-angle near 87°. )
AUGITE (DARK PYROXENE): Average composition, MgO 12 to 18,
CaO 18 to 20, FeO 10 to 13, APO3 4 to 8, SiO2 47 to 50, with small
amounts of MnO, &c. Clino-Rh. ; the more common crystals are
_ /
eight-sided prisms, composed of the forms V, Y, and V, with two
inclined summit-planes, or large basal plane*. Often twinned parallel
to V (see Note at end of Table). Y : Y 87° 6'; Y on Y 90°; angle
over summit-planes 120° 48'. Commonly, in cleavable, fibrous, or
granular masses. Black, greenish-black, dark-green, dark-brown ;
H 5-0-6-0; G 3-0-3-4. BB, fusible more or less easily into a
black, generally magnetic bead. Hedenbergite is a non-magnesian
augite, consisting of CaO 22-18,FeO 29'43,SiO248-39: black, blackish-
green, in cleavable masses. Coccolite is a dark-green augite, occuriiig
in granular masses or small crystals with rounded edges and angles.
Breislakite is an acicular variety from Italian lavas. Fassaite
(Pyrgom), and some Sahlites also belong to the present sub-species.
ACMITE: WO 13-88, FeO 6-45, Fe2O3 28-64J, SiO2 51-03, with
small amounts of K2O, MnO, TiO2, &c. Clino-Rh.; crystals long
and thin ; striated longitudinally, and, as regards the typical examples,
imbedded in quartz ; Y on Y 87° 15'; H 6-0-6-5 ; G 3-4-3-53. Easily
* This plane is regarded by most Germaii crystallographers, and by many others, as a front -
polar or hemi-orthodome. See the note on the crystallization of Pyroxene at the end of the
present Table.
f Some mineralogists make all the iron Fe203, but FeO is certainly present in Acmite as well.
MINERAL TABLES : — xxvl. 233
fusible into a black magnetic bead. ^Egirine is identical or closely
related.
JEFFERSONITE : CaO, MgO, MnO, ZnO, FeO, SiO2, with small
amounts of A12O3, &c." Clino-Rh., but occurring only in granular
examples with cleavage-angle of about 87° 30'. Dark-green, brown,
greenish-black ; H 4-5 ; G 3'3-3'5. BB, fusible into a black bead.
With carb. soda and borax on charcoal, gives a zinc sublimate and
strong manganese reaction. Hitherto, only met with at Sparta, New
Jersey.*
BABINGTONITE : CaO 19-32, MnO 7-91, FeO 10-26, Fe2O3 11-00,
SiO2 51*22, with traces of MgO, &c. Anorthic (crystals mostly short,
eight-sided prisms, with two summit-planes). Occurs also in radiating
groups. Black, greenish -black ; H 5-5-6-0 ; G 3-3-3-4. Easily fusible
into a black magnetic bead. Generally associated with Albite or Ortho-
clase. Distinguished from black augite only by its crystallization.
RHODONITE (Silicate of Manganese): MnO 54-2, SiO2 45-8, but
part of the MnO commonly replaced by CaO, FeO, or MgO. Anor-
thic, but crystals of exceedingly rare occurrence ; commonly in cleav-
able masses, with cleavage-angle of 87° 38'; rose-red, greyish-red,
weathering dark-brown; H 5'0-5'5; G 3-5-3'65. BB, fusible into
a dark-red or amethystine glass which becomes black and opaque in
the outer flame. With carb, soda, strong Mn reaction. Bustamite,
in radiated-fibrous examples of pink or pale greenish-grey colour, is a
calcareous variety ; Fowlerite, in coarse crystals and cleavable masses
of a reddish-brown or dull-red colour, has the MnO largely replaced
by FeO, CaO, and ZnO.
(In lamellar or fibrous masses or in distinct crystals with cleavaye- angle and
principal prism-angle near 124°).
HORNBLENDE ; DARK OR STRONGLY-COLOURED AMPHIBOLE (In-
cludes Common Hornblende, Basaltic Hornblende, Pargasite, and
most examples of Actynolite) : Average composition, CaO 9 to 12,
MgO 10 to 20, FeO 8 to 20, Fe203 5 to 6, A1203 5 to 15, SiO2 40 to
44 ; but in non-aluminous or slightly aluminous varieties, the SiO2
generally exceeds 50 per cent. Small amounts of Na2O, K2O, and
Fluorine are also usually present. Clino-Rhombic ; crystals mostly
,'
six-sided prisms, composed of the forms Y and Y, terminated generally
* As the composition of Jeffersouite does not appear to be at all constant, the mineral may
perhaps be nothing more than a mixture of Pyroxene and Franklinite.
234 BLOWPIPE PRACTICE.
by three comparatively flat rhombiform faces ( = B and P), also some-
times consisting of the prism V alone, terminated by two triangular
/ /
planes P. The front prism-angle V on V equals 124° 30': V on V
= 117° 45'; P on P=148P 30'; P on B= 145° 35'; P on P (over
summit) = 148° 16'. Occurs also very abundantly in lamellar,
fibrous and granular masses ; colour, dark-green, black, dark-brown ;
H 5-0-8-0 ; G 3-0-3-4. BB, fusible more or less easily into a blffck,
usually magnetic bead. Cummingtonite is a brown, fibrous variety,
containing very little lime. Arvedsonite is a closely-related species
or variety containing 10-60 per cent. Na2O. Mostly in black cleav-
able masses, with greenish streak ; H 6-0 : G 3-33-3-60. Very easily
fusible, with much bubbling, into a black, magnetic bead*. See also
Glaucophane, under B3, below.
(In amorphous, obsidian-like masses.)
WICHTISITE (Wichtyne) : Xa'O, CaO, MgO, FeO, Fe203, A12O3,
SiO2. In black, more or less dull, amorphous masses, with well-
marked conchoidal fracture; H 6-0-6-5; G 3-0-3-1. Fusible, with
bubbling, into a black opaque bead.
(In deep-red grains and rounded crystals.)
PYROPE (Bohemian Garnet) : See under Garnet, above.
(In flat tabular crystals or granular masses. Sp. (jr. over 3*5.)
CERINE : Black, brownish-black ; scarcely attacked by hydrochloric
acid. See under Orthite, above, page 228.
B. — Fusible into a colourless or lightly-tinted bead or glass.
BI.— IMPART A DISTINCT RED OR GREEN COLOUR TO THE BLOWPIPE-FLAME.
f BB, flame coloured red.
(Soft ; scaly or foliated. )
LEPIDOLITE (Lithionite, Lithia Mica): K2O 4 to 11, Na2O 1 to 3,
Li2O 1-5-5; MnO 2 to 5, APO3 14 to .29, Fe?O3 0 to 28, SiO'2 40 to
52, with from 4 to 8 per cent. Fluorine. Essentially in scaly aggre-
gations or micaceous masses of a rose-red, pale-red, pearl-grey, or
greyish-white colour; H 2-0-4-0 (commonly 2-5); G 2-8-3-0. BB,
very easily fusible with great bubbling into a colourless blebby gla^s
* Very thin splinters fuse without the aid of the blowpipe, as Grst pointed out by Dr. L. H.
Fischer : Clavis der Silicate, p. 11.
MINERAL TABLES : XXVI. 235
(or, as regards ferruginous examples, into a dark metallic bead), with
crimson coloration of the flame. In the spectroscope, the red Li-line
and yellow Na-line come out very prominently, the red K-line sub-
ordinately*. After fusion, completely decomposed by hydrochloric
acid.
CRYOPHYLLITE : K20, Li20, MgO, MnO, FeO, Fe203, APO3, SiO2
(53-46) with 2 to 3 Fluorine. Essentially in dark-green, six-sided,
micaceous prisms and scaly masses; G 2 -9. BB, colours the flame
red, and fuses with great bubbling.
(Hard. Not micaceous in structure. ) •
PETALITE : Li2O (with small amount of Na20) 4-42, A1203 17-80,
SiO* 77-96. Essentially in lamellar masses (Clino-Rh.) with cleavage-
angles of 117°, 141° 23' and 101° 30', but the two latter often indis-
tinct ; colour, pale-red, reddish- white, or nearly colourless ; H 6 '0-6 -5 ;
G 2 -4-2 -6. BB, colours flame pale-red, and melts to a colourless
glass. In the spectroscope, especially if the test-matter be moistened
with hydrochloric acid, the red Li-line comes out very distinctly.
Insoluble in acids. Kastor is a variety in coarse Clino-rhombic
crystals from Elba : "V on V 86° 20'.
SPODUMENE (Triphane): Li2O 6-73, APO3 29-21, SiO2 64-06; but
part of the LPO commonly replaced by small amounts of Na2O and
K2O and. traces of CaO. Clino-Rhombic, with V :-V 87°, but crystals
comparatively rare. Commonly in cleavable masses with cleavage-
angles of 87? = V : V, and 133° 30' = Y : V. Pale-green, greenish-
white, or greenish-grey; H 6-0-7-0; G 3-12-3-20. BB, colours
flame distinctly red, and melts easily, with much expansion and
bubbling, into a colourless glass. Insoluble in acids. In spectroscope,
shews red Li-line and yellow Na-line distinctly.
f f Flame coloured green.
( Very easily fusible. )
AXINITE : Essentially in groups of thin sharp-edged crystals, brown,
green, brownish violet, pearl-grey, or amethystine in colour. BB,
melts in the outer flame into a black glass, and with carb. soda gives
manganese reaction. See above, page 230.
* The K-line is scarcely visible unless the Na and Li lines be cut off by the intervention of \
piece of deep-blue glass*
236 BLOWPIPE PRACTICE.
DANBURITE : CaO 22-75, B2O8 28-45, SiO2 48-80. Anorthic ; but
mostly in lamellar massess with cleavage-angles of 110°, 126° and 93°,
the two latter more or less indistinct. Yellowish-white, pale-yellow ;
H 7-0 ; G 2-95-2-96. BB, easily fusible, with green coloration of
the flame. The powder moistened after ignition with hydrochloric-
acid, shews in the spectroscope green B-lines with transitory flashes
of the red Ca-line.
(Fusible with difficulty or on the edges only. )
HYALOPHANE (Barytic Feldspar) : K20 7-82, Na2O 2-14, BaO 15-05,
A12O3 21-12, SiO2 52-67, with traces of CaO, MgO, &c., but the com-
position, more especially as regards the amount of baryta, appears to
be somewhat variable. Clino-Rhombic ; crystals practically identical
with those of Orthoclase ; cleavage very perfect parallel with basal
plane; white, pale-reddish; H 6-0-6-5; G 2-80. BB, fusible on
edges only, unless in thin splinters. Distinguished from the feldspars,
generally, by the green colour imparted to the point of the flame. In
acids scarcely attacked.
B2.— YIELD STRONG REACTION OF SULPHUR OR CHLORINE.*
t Give sulphur reaction, BB, with carb. soda.
HELVINE ; DANALITE : Essentially in small tetrahedrons or octahe-
drons, or in small grains, of a yellow, brownish, yellowish-green, or
reddish-grey colour. H 5'5-6-5 ; G 3'2-3'4. Gelatinize and evolve
odour of sulph. hydrogen in hydrochloric acid. BB, in* outer flame
giv^e a black or dark fusion-product. See under A2, page 229.
HAUYNE: K2O 4-96, Na2O 11-79, CaO 10-60, A12O3 27-64, SiO2
34-06, SO3 11-25. Reg.; chief crystal form, the rhombic dodecahe-
dron ; occurs also in small grains. Essentially blue or bluish-green,
rarely colourless (Berzeline); H 5-0-5-5; G 2'4-2-5. BB, decrepitates,
and melts slowly into a pale-blue or colourless glass. Gelatinizes in
hydrochloric acid.
NOSINE (Nosean): NaO, A1203, SiO2, SO3. Closely resembles
Hauyne in crystallization, and in its blowpipe and acid reactions,
but commonly ash-grey, greyish-blue, or greenish-white in colour,
and with larger percentage of soda (24-89).
* See page 61, Experiments 1 and 3. In testing for sulphur, the reagent, carb. soda, should
be used somewhat in excess.
MINERAL TABLES : XXVI. 237
LAPIS-LAZULI : NaO, CaO, SiO2, SO3, &c. Essentially in granular
masses of a rich blue colour, frequently intermixed with calciter
grains of iron pyrites, and other substances. When crystallized, in
rhombic dodecahedrons. H 5*5 ; G 2-38-2-45 ; BB, melts easily to
a colourless glass. Gelatinizes in hydrochloric acid, most examples
evolving sulph. hydrogen during decomposition.
MICROSOMMITE : Gives feeble S-reaction, but strong reaction of
chlorine : see below.
1 1 Give Cl-reaction with cupreous phosphor-salt bead.
SODALITE : Na2O, A12O3, SiO2, NaCl. Reg. ; chiefly crystallized
in rhombic dodecahedrons, or in combinations of that form and the
cube ; occurs also in granular examples ; mostly colourless or green-
ish-white, less commonly blue or bluish-green. H 5-5 ; G 2-13-2-30,
BB, a colourless glass. In hydrochloric acid, gelatinizes.
MICROSOMMITE : K2O, Na2O, CaO, A12O3, SiO2, NaCl, with small
percentage of SO3 in most examples. Hexagonal ; chiefly in minute
six-sided prisms on certain Yesuvian lavas; H 6'0; G 2-6. BB,
according to Sacchi, difficulty fusible. Gelatinizes in hydrochloric
acid. The spectroscope should shew Na, K, and Ca lines, but the
writer has not been able to procure a specimen for examination.
EUDIALYTE : Na2O, CaO, FeO, ZrO2, SiO2, with small amounts of
CaO, MnO, &c., and about 2 per cent. NaCl. Hemi-Hexagonal; crys-
tals, acute rhombohedrons with extended basal plane; R : R 73° 30',
B:R 112° 18' and 67° 42'. Dark purplish-red, brownish-red.
H 5-0-5-5; G 2-8-3-0. Melts easily to a greyish-green glass or
Hiiamel. Gelatinizes in hydrochloric acid. Eucolite from Norway
is closely related. Both are rare species.
R*.-NO DISTINCT (RED OR GREEN) FLAME-COLORATION. NO REACTION OF
SULPHUR OR CHLORINE.
f Decomposed with gelatinization by hydrochloric acid.
(BB, with carb. soda on charcoal, a distinct sublimate).
EULYTINE (Bismuth Blende): Bi2O3 83-75, SiO2 16-25, but gen-
erally intermixed with Fe2O3, Mn2Os, P2O5, Fl, &c. Reg. : crystals
essentially tetrahedral, very small, in drusy aggregations; occurs
also in botryoidal masses; H 4-5-5-0; G about 6*1. Fusible into a
dull brownish bead. With carb. soda forms on charcoal a deep-
yellow sublimate. Gelatinizes in hydrochloric acid.
238 BLOWPIPE PRACTICE.
WILLEMITE : ZnO, SiO2. White, brownish, &c. Fuses on edges
or surface only. With carb. soda and borax on charcoal gives a
zinc-sublimate. With Co-solution, coloured blue or bluish-green.
See TABLE XXV.
(BB, with carb. soda no sublimate. Colour, black).
GADOLINITE : Essentially in small, vitreo-resinous masses of a
black colour and greenish-grey streak. BB, generally swells up,
but vitrifies on edges only. See TABLE XXIV.
TSCHEWKINITE : CaO, MnO, FeO, CeO, LnO, DO, TiO2, SiO2,
with traces of K2O, Na2O, &c. In more or less compact masses ;
velvet-black, with brownish streak; H 5*0-5-5 ; G 4-5-4-8. BB,
swells up into a porous mass, and then melts slowly into a dull yel-
lowish enamel. Gelatinizes in hydrochloric acid. The diluted solu-
tion boiled with a piece of metallic tin assumes a violet colour. A
very rare species.
(Colourless or lightly -tinted species. Fusible on thin edges, only).
GEHLENITE : Essentially in greenish-grey, or pale-brownish, square
prisms of small size. Ca-lines in spectroscope readily brought out
by moistening the ignited test-substance with hydrochloric acid. See
TABLE XXIV.
MONTICELLITE (Batrachite) : Essentially in small crystals of the
Rhombic System. V:V 98° 8', VJ : VJ 133°, P : P over summit
82° nearly, P:P over front edge 141° 50'; over side edge 82°.
Colourless, pale-green, pale-brownish. Other characters as in Geli-
lenite. See TABLE XXIV.
(In platinum forceps, more or less readily fusible. In spectroscope, after ignition
and moistening with hydrochloric acid, shew distinct red and green Ca-lines).
WOLLASTONITE (Table Spar): CaO 48*28, SiO2 5172. Clino-
Rhombic, but crystals comparatively rare; commonly in lamellar
and fibrous masses, with cleavage angles of 95° 30' and 84° 30' ( = B
on V) ; colourless, pale-reddish or yellowish-white, &c. ; H 4-5-5*0;
G 2*75-2*92 ; in the forceps, thin splinters fuse more or less readily.
Decomposed, with gelatinization by hydrochloric acid.
HUMBOLDTILITE (Melilite) : Na2O, CaO (31 or 32), MgO, Fe2O3,
A12O3, SiO2. Tetrag.; crystals mostly tabular, with large basal
plane.; occurs also in fibrous and columnar examples; yellowish-
white, pale-yellow, brownish, <fec. ; H 5*0-5*5; G 2*9-2-95. BB,
MINERAL TABLES : — XXVI. 239
fusible with slight bubbling into a colourless or yellowish glass.
Gelatinizes in hydrochloric acid.
SARCOLITE : K2O 1-20, Na2O 3-30, CaO 32-36, Al'O3 21-54, SiO2
40*51 (Rommelsberg). Tetrag. ; crystals, mostly small square prisms
with replaced angles ( = V, B, P) ; also sometimes with hemihedral
polar planes; pale-red, reddish-white; H 5.5-6-0; G 2-55-2-95 ;
fusible into a white blebby glass or enamel. In hydrochloric acid,
gelatinizes.
DAVYNE ; CANCRINITE : See under Nepheline, below.
(No Ca-lines brought out in spectroscope by moistening with hydrochloric
acid*).
NEPHELINE (Elreolite) : K2O 4-5 to 6-5, Na2O 15.5 to 17, APO:
34-5 to 35-5, SiO2 41 to 45. Hexag.; crystals mostly small hexa-
gonal prisms with replaced basal edges ; occurs also in lamellar
masses; colourless, white, pale-brownish, with. vitreous lustre (Ne-
pheline proper) ; and greyish-blue, bluish-green, or red, with vitreo-
resinous lustre (Elteolite) ; H 5-5-6-0; G 2-55-2-65. Fusible, with
more or less bubbling, into a blebby glass. Gelatinizes in hydro-
chloric acid. Most examples shew the red K-line distinctly in the
spectroscope if moistened with HC1 acid after fusion or ignition.
Davyne and Cancrinite are partly altered varieties, containing inter-
mixed CaO, CO2, and a small percentage of H2O.
1 1 Decomposed by hydrochloric acid, but without gelatinization. f
( The hydrochloric acid solution boiled with tin assumes a blue or
violet colour).
SPHENE (Titanite) : CaO, TiO2, SiO2. In Clino-Rhombic crystals
and cleavable masses of a brown, yellow, yellowish -grey or green
colour; H 5-0-5-5; G 3-4-3-6. BB, melts generally into a black or
dark enamel, but in some cases the fusion product is dull-yellow.
See under B1, above, page 229.
GUARINITE : CaO, TiO2, SiO3. Rhombic, but hitherto only recog-
nized in apparently square tables. Sulphur-yellow. Fusible into a
yellow glass.
* Unless intermixed calcite be present, as in many examples of the Davyne and Cancrinitr
varieties.
f In some cases, the decomposition, although sufficiently marked, is more or less in^orri-
plete. If decomposition ensue at all, the supernatant liquid, diluted slightly and filtered from
the undissolved residuum, will yield a distinct precipitate with ammonia, or witli oxalate (.f
ammonia>dded subsequently.
-40 BLOWPIPE PRACTICE.
WOHLERITE : Na2O, CaO, FeO, ZrO2, Nb205, SiO2. Rhombic or
Clino-Rhombic, but crystals mostly indistinct ; commonly in small
angular grains, or in sub-columnar masses and indistinct tabular
forms. Yellow of various shades, yellowish-brown; H 5-0-6-0;
G 3-41. BB melts easily into a yellowish bead. Hitherto only
found in the Zircon-syenite of Norway.
(Giving BB with fused phosphor-salt in open glass tube a strong
Fluorine-reaction) ,
LEUCOPHANE: CaO, BeO, SiO2, NaF. Essentially in cleavable
lamellar masses of a pale yellow or greenish-grey colour. H 3 -5-4-0;
G 2*9-3. Strongly phosphorescent, and very easily fusible. Slowly
decomposed by hydrochloric acid. See under the Fluorides, in Table
XX, page 178. A rare species.
MELINOPHANE (Meliphanite) : CaO, BeO, SiO2, NaF. Occasion-
ally in Tetragonal crystals, but commonly in lamellar masses and
disseminated grains of a yellow colour ; H 5*0 ; G 3.02. BB, easily
fusible (but is said not to phosphoresce?). Very rare, and still im-
perfectly known.
(Fusible on charcoal into a glassy bead).
PREHNITE*: CaO 27-14, A12O3 24-87, SiO" 43-63, H2O 4-36.
Rhombic ; crystals tabular or short prismatic, generally aggregated
in groups ; occurs also abundantly in fibrous- botryoidal masses, and
sometimes in pseudomorphs after calcite, analcfme, &c. ; H G-0-7'0 ;
G 2-8-3-0; generally greenish-white, also colourless and light-green.
Fuses very easily and with much bubbling. In the bulb-tube, gives
off a small amount of water, but only at a comparatively high tem-
perature. After fusion or strong ignition, decomposed with gelatin-
ization by hydrochloric acid, and then shews in spectroscope momen-
tary red and green Ca-lines.
WERNERITE (^Scapolite, Paranthine, Meionite, &c.) : Contains CaO,
APOa, SiO2, in somewhat variable proportions, with small amounts
of K2O, Na2O, and IPO. Tetragonal; crystals, commonly, eight-
sided prisms composed of the two square prisms V and V, with ter-
minal polar planeSj P, P, &c. (See note at end of Table). P : P
over middle edge 63° 42', over polar edge 136° 11' ; cleavage parallel
with V, less distinct parallel with Y; crystals often large, and fre-
* Belongs properly to Table XXVII. , but is referred to also here, as the small amount of
water which it contains might in certain cases escape detection.
MINERAL TABLES : XXVI. 241
quently more or less weathered ; occurs also in columnar, sub-fibrous,
granular, and other masses ; colourless, white, greenish-white, green,
pale-reddish, greyish, &c.; H 5'0-6'Oj G 2-6-2-8. BB, easily fusible
with more or less bubbling. In the spectroscope, after ignition and
moistening with hydrochloric acid, shews red and green Ca-lines, in
most cases, very distinctly. Meionite (often classed as a distinct
species) and Mizzonite are varieties from Monte Sornma. Nuttalite,
Dipyre, Couseranite, Passauite, are varieties from other localities.
Wilsonite, in pale • purplish-red, cleavable and sub-fibrous masses, is
probably an altered Wernerite containing intermixed CaOCO2.
GROSSULAR, and most other light-coloured GARNETS :* CaO, Ala03,
SiO2, &c. In crystals of the Regular System, chiefly the rhombic
dodecahedron or the trapezohedron 2-2, and in small rounded grains ;:
H 6-5-7-5; G 3-15-3-8 (in grossular, proper, usually about 3*4 or
3-5); light-green, (grossular prope^), red, yellow, brown, etc., rarely
colourless. BB, more or less readily fusible into a lightb
uncoloured glass.
(Fusible in the forceps, but not fusible into a bead on
ANORTHITE (Lime-Feldspar in part, Indianite, Christianize).:
2010, A1203 36-82, SiO2 43-08. Anorthic; crystals often largo,
/
with B and V planes predominating ; frequently twinned parallel to-
one or the other of these forms, to which the cleavage planes are
also parallel; cleavage-angles, 85° 50' and 94° 10'; Right V on
Left V 120° 30'. Occurs also in lamellar and granular masses;
H 6-0; G 2-66-2-80; colourless, white, pale-reddish, with pearly
lustre on cleavage planes and vitreous lustre on other planes. BB,
fusible into a clear glass. Completely decomposed by hydrochloric
acid, but without gelatinization. In the spectroscope, the Ca-lines
come out distinctly after ignition and moistening with acid.
LABRADORITE (Lime Feldspar, Lime-soda Feldspar, Labrador Feld-
spar) : NaO, CaO, APO3, SiO2. Anorthic ; but commonly in cleav-
able masses, with cleavage-angles of 86° 40' and 93° 20' ; mostly light
or dark grey, with play of green, blue, violet, red, or orange, in
certain directions, but sometimes white, and without or with very
* The deep-red and most dark garnets fuse into a black and generally magnetic bead, and
are thus placed in section A of the present Table. Many light garnets, again, are partially
decomposed by hydrochloric acid, whilst others are scarcely attacked by that reagent. These
latter are referred to, consequently, under the next sub-section 1 1 1-
17
242 BLOWPIPE PRACTICE.
feeble play of colour. H 6'0; G 2-6-2-8. Fusible into a clear glass.
Slowly and only partially decomposed by hydrochloric acid. Spec-
troscope reaction as in Anorthite.
f f f Scarcely attacked by hydrochloric acid.
(Micaceous species : flexible in thin leaves. Fusible on edges or in ihvn
scales, only*.)
MUSCOVITE (Potash Mica) ; PHLOGOPITE (Potassic Magnesian
Mica ) : In thin leaves, flexible and elastic ; lustre more or les
metallic-pearly. Phlogopite is decomposed by sulphuric acid ; Mus-
covite, not. Both fuse in general on the edges into a grey enamel.
Biotite is also decomposed by sulphuric acid, but melts on the
edges, as a rule, into a black ferruginous glass or slag. See TABLE
XXV., A1.
TALC : MgO, SiO2. White, greenish, &c. ; very soft. Flexible
in thin pieces, but not elastic; H'1'0. More or less soapy to the
touch. Reddens by ignition with Co-solution. See TABLE XXV., A2.
(Foliated species, with marked cleavage in one direction, but not flexible in
thin
MARGARITE (Pearl Mica) : White, reddish, greenish, &c., with
pearly lustre ; H 3'5-4'0. Fusible on the edges, often with more or
less intumescence, into a greyish enamel. See TABLE XXV.
DIALLAGE : MgO, CaO, SiO2, with, commonly, small amounts of
FeO, MnO, APO3, and H2O. In foliated or sub-foliated masses or
indistinct tabular crystals of a greyish-green or greenish-brovra
colour and metallic-pearly lustre; H about 4-0; G 3'2-3*4. Fusible
more or less easily into a greyish enamel. An aberrant, schistose
variety of Pyroxene.
( Very sectile : readily cut by the knife. Fusible on edges only).
STEATITE (Soapstone in part) : MgO, SiO2. In white, grey, green-
ish, reddish, or mottled masses of more or less compact structure, or
occasionally sub-slaty. Sometimes, also, in pseudomorphs after Scapo-
lite, Spinel) and other species ; H 1-5-2-5. BB, hardens greatly, but
only fuses on thin edges. Reddens by ignition with Co-solution.
Generally gives off traces of water in the bulb-tube. Decomposed
by sulphuric acid. A compact or non- foliated variety of Talc. See
TABLE XXV., C>.
* Most of these species, when ignited in the bulb-tube, give off traces of water.
MINERAL TABLES : — XXVI. 243
(Asbestiform : in soft, fibrous masses).
ASBESTUS (Amianthus) : Essential components, CaO, MgO, SiO8.
In white, grey, brownish, greenish-white, or green masses of fibrous
structure, more or less soft and silky. Readily fusible into a colour-
less or pale greenish glass. A fibrous variety of Amphibole or Py-
roxene. Passes into fibrous serpentine, but distinguished properly
from the latter by not being decomposed by sulphuric acid, and by
yielding merely traces of water in the bulb-tube. Also by its greater
fusibility.
(Sp. gr. 2-9 or higher. In most cases, distinctly over 3'0).
DIOPSIDE, and other light-coloured PYROXENES (Malacolite, Alalite,
Sahlite in part) : Average composition, MgO 18, CaO 26, SiO2 56 ;
but in some cases 5 or 6 per cent. APO3, and only 50 or 51 per cent.
SiO2 are present. Clino-Rhombic ; crystals, as in Augite (see above),
commonly eight-sided prisms made up of the forms Y, Y, and Y, and
terminated by several polar forms or by a large basal plane.* Y:Y
87° 6'; Y:Y 133° 33'; Y:Y 136° 27'; B:Y 105° 30'. Occurs
also abundantly in lamellar and other conditions, with cleavage
angles of about 87° and 93°. Usually greenish-white or some light
shade of green, passing into deeper green; H 5'0-6'0; G 3'0-3'4.
BB, in thin splinters, fuses more or less readily into a colourless or
lightly-tinted glass.
TREMOLITE, and other light-coloured AMPHIBOLES (Grammatite,
Actiiiolite in part, Nephrite in part, Smaragdite) : Average compo-
sition, CaO 13*5, MgO 28-5, SiO2 58; but in some varieties a small
amount of A12O3 is present, with corresponding decrease of SiO2.
Many examples also contain 1 or 2 per cent, of fluorine. Clino-Rhom-
bic ; crystals commonly oblique-rhombic prisms composed of the four
planes Y, with two depressed triangular planes or side-polars P at
each extremity; or sometimes six-sided, from presence of Y; the
basal form B also often present. Y:Y 124° 30'; Y:Y 117° 45';
/ /•
P : P 148° 16'. Occurs likewise very abundantly in fibrous and
lamellar masses, with cleavage-angle of 124° 30'; H 5-0-6-0; G 2-9-
3-2 ; colourless, but more generally greenish-white or some pale
*This plane is regarded by many crystallographers as a front-polar or hemi-orthodorue. See
the note on Pyroxene at the end of the present Table.
244 BLOWPIPE PRACTICE.
shade of green, passing into grass-green and other deeper shades.
BB, in thin splinters, more or less easily fusible.
GLAUCOPHANE: Na2O 7-33, CaO 2-20, MgO 13-07, FeO 5-78,
APO3 12-03, Fe203 2-17, SiO2 57-81. Clino-Rhombic, with Y on Y
(as in Amphibole) 124° 30'-125°; crystals, mostly long flat prisms,
vertically striated, and passing into fibrous masses; H 5 '5-6-5 ;
G 3-1-3-2 ; dark greyish-blue, bluish-black; BB, easily fusible into
a greenish glass. A rare species, hitherto only obtained from the
Island of Syra.
ZOIZITE : CaO 24, APO3 30, SiO2 41, with small amounts of MgO
and Fe2O3, and about 2 per cent, of basic water, the latter not revealed
by ordinary ignition in the bulb-tube. Rhombic or Clino-Rhombic 7
but crystals more or less indistinctly formed ; commonly in bladed
or sub-columnar examples, longitudinally striated. White, pale-grey,
pale-greenish, yellowish, or red; H 6-0; G 3-1-3-4. BB, swells up,
emits a few bubbles, and melts, if in thin splinters, into a colourless
glass. After fusion or strong ignition, is decomposed with gelatini-
zation by hydrochloric acid, and then shews in the spectroscope mo-
mentary red and green Ca-lines. Thulite is a rose-red variety, con-
taining a small percentage of Mii203. Unionite is a white variety.
TOURMALINE : Black varieties (SCHORL) and some Brown varieties :
MgO, FeO, MnOj APO3, B2O3, SiO2. Hemi-Hexagonal, mostly in
three-sided or nine-sided prisms, or in fibrous and columnar masses
of a jet-bkck or brown colour; H 7'0-7'5 ; G 3-0-3-2. Fuses
generally into a black or dark slag, but sometimes into a dull-
yellowish or more or less uncoloured glass or enamel. The fused
mass crushed to powder and moistened with sulphuric acid imparts
a distinct green coloration to the flame-border. See above, under
A? tttt.
YESUVIAN (Idocrase, Egeraiie) : Average composition, CaO 30 to
34; MnO, FeO, MgO, 5 to 8; Fe2O3, A12O3, 18 to 20, SiO2 37 to
39, with small amount of alkalies and basic H2N. Tetragonal ;
crystals, commonly, square prisms (or 8-sided prisms composed of the
two square prisms Y, Y) terminated by the pyramid P and a well-
developed base, B : the latter form very rarely absent. B on P
142° 45' to 142° 57'. Occurs also in columnar and granular masses;
H 6-5; G 3-33-3-45; dark-brown, yellowish-brown, brownish-red,
yellow, green of various shades, rarely blue. BB, melts, usually
MINERAL TABLES : — XXVI. 245
with slight bubbling, into a lightly-tinted glass. This, when crushed,
•dissolves with gelatinization in hydrochloric acid, and then shews
momentary red and green Ca-lines in the spectroscope. Cyprine is a
folue variety containing a small percentage of CuO. Wiluite,
Egerane, Xanthite, Loboite, Frugardite, Heteromerite, are other
varieties. Colophonite, in yellow or brown grains and rounded
masses, commonly referred to Garnet, is also as regards most examples
a Vesuvian. Practically, however, Vesuvian and Garnet can scarcely
<be distinguished from each other, except by their .crystallization.
GARNET : Light coloured varieties : CaO, A12O3, SiO2, <fec. Essen-
tially in rhombic dodecahedrons or trapezohedrons, or in rounded
.grains, of a red, yellow, brown, or green colour; H T'0-7'5; G
3'2-3'8. More or less readily fusible into a colourless or lightly
tinted glass. See also under ff and A2 of this Table.
(Sp. gr. under 2~8, in most c.ase-s about 2*6. Fusible, unless In fine splinters,
on the edges only),
ORTHOCLASE (Common or Potash Feldspar) : K20 16'9, A12O3 18'4,
SiO2 64*7, but, very generally, small portions of Na?O, <fcc., are also
present. Clino-Rhombic ; crystals frequently flattened parallel with
the side-vertical planes, and often extended in that direction; twins
^Tery common: see Note at end of TABLE. Prism-angle 118° 47'.
Occurs also abundantly in cleavable, lamellar masses, the cleavage
planes ( = B, V) meeting at right-angles. H 6'0 ; G 2'53-2'58 ;
colourless, white, flesh-red, bright-red, light-green, pale-yellowish,
light-grey ; somewhat pearly on cleavage- planes ; iridescent in some
varieties, and occasionally opalescent. BB, fusible 011 the edges only,
unless in the form of a thin pointed spliater, in which ease the
extremity is quickly rounded into a clear glass. Ignited, and then
fused with carb. soda or fluor spar, or simply moistened with hydro-
chloric acid after ignition, shews in spectroscope the red K-line very
distinctly. All other lines (derived from the soda or fluor spar) may
be entirely obliterated by the intervention of a piece of blue glass.
Adularia, Sanidine or Ryacolite (often called glassy feldspar), Peg-
matolite, Ac., are varieties. Loxoclase is also a variety, but resembles
Oiigoclase in composition. Perthite is a dark red-brown iridescent
mixture of Orthoclase and Albite, the iridescence derived from minute
scales of Iron Glance.
246 BLOWPIPE PRACTICE.
MICROCLINE :* A potassic feldspar closely allied to Orthoclase, but
apparently anortliic (triciinic) in crystallization. The cleavage angle
only differs, however, from a right angle by 15 or 16 minutes; and
the prism-angle (118° 31') and other angles scarcely differ from
corresponding angles in Orthoclase. Most of the green feldspars
(commonly called Amazon Stone) are supposed to be referrible to
Microcline ; but the species (?) can only be distinguished from Ortho-
clase by minute optical investigation.
HYALOPHANE : A barytic feldspar, almost identical with Orthoclase
in crystallization. G2:8; white or flesh-red. BB, tinges the flame-
point pale-green. See under ff of this section.
ALBITE (Soda Feldspar): Na2O 11-82, A12O3 19-56, SiO2 68-62,
but 1 or 2 per cent, of the Na2O commonly replaced by K2O. Anor-
thic ; but crystals generally clino-rhombic in aspect, and much like
those of Orthoclase: see Note at close of Table. Prism-angle 120°
47' ) cleavage-angles 86° 24' and 93° 36'. Crystals commonly in
twinned or compound forms, rarely simple. Occurs also abundantly
in lamellar masses, with, cleavage as above ; colourless, white, light-
red, light-green, yellowish, brownish, &c. ; H 6-0 (or 6-0-6-5) ; G
2-59-2-64. BB, like Orthoclase, but colours the flame more or less
strongly yellow : the two species, however, can only be distinguished
by their crystallization, or by accurate chemical analysis, although if
the red K-line be distinctly obtained in the spectroscope, the sub-
stance, as a rule, may be safely -regarded as Orthoclase (or Microcline).
- See under Orthoclase, above. Pericline is a white opaque or feebly-
translucent variety in crystals elongated more or less in the direction
of the right-and-left axis, frequently twinned, and strongly striated
/
on the side-vertical faces V. Peristerite is a white, slightly iridescent
variety. Olafite, Cleavelandite, and Zygadite, are other varieties.
OLIGOCLASE (Soda-lime Feldspar) : Na20 (slightly replaced by
K2O), CaO, A12O3, SiO2. Anorthic; crystals much like those of
Albite, with prism-angle 120° 42' to 120° 53', and cleavage-angles of
about 86° 10' (or 86° 30'), and 93° 50' (or 93° 30'). Principal
cleavage-plane (B), delicately striated ; twin-crystals, very frequent.
Occurs also in lamellar and fine-granular masses. H 6'0; G 2 '6-2 '66;
white, pale-red, greenish-grey, &c., with somewhat waxy lustre ;
* Of Des-Cloizeaux, not Breithaupt. The Microcline of the -latter is the iridescent Orthoclase
from the zircon-syenite of Norway.
MINERAL TABLES : — XXVI. 247
occasionally iridescent. BB, fuses, in thin splinters, into a colourless
glass. Apart from its more ready fusibility, this species can scarcely
be distinguished from Albite, except by actual analysis.
(Sp. gr. under 2*5. Compact structure. Very easily fusible),
OBSIDIAN : K20, Na2O, A1203, SiO2, with small amounts of CaO,
Fe2O3, &c. In amorphous masses, breaking with conchoidal fracture
into glassy sharp-edged fragments. H 6'0-7'0 ; G 2'2-24. Black,
brown, grey, greenish, <fec., sometimes striped or zoned in different
shades ; translucent to opaque. Easily fusible with bubbling into a
white glass or enamel. Pitch stone is a less vitreous, coarser variety.
Pearlstone is a closely related substance, made up essentially of small
pearly concretions, or containing these in a vitreous obsidian-like
paste. All are volcanic products : rather rocks than minerals proper.
NOTE ON TABLE XXVI.
This Table consists entirely of silicates, distinguished from other compounds
of that class by being distinctly fusible, and by yielding no water (or merely
traces) when ignited in the bulb- tube. All give the characteristic reaction of
silicates by fusion with phosphor-salt — a silica-skeleton separating, whilst the
bases dissolve in the' flux. In some cases, a portion of the silica is dissolved
also, but this precipitates on cooling, and the bead becomes more or less
opalescent or clouded. The more commonly occurring minerals of the Table
comprise representatives of the following series : Micas, Boro- Silicates, Garnets,
Epidotes, Iron Chrysolites, Pyroxenes and Ainphiboles, Scapolites, Feldspars.
The Mica Group, as regards the present Table, is chiefly represented by
Lepidolite — the ordinary micas, Muscovite, Phlogopite, and Biotite, being as
a rule fusible only when in very thin scales, and often on the edges only.
Hence, these latter species are described in Table XXV. , and in the Note to
that Table. Lepidolite is easily recognized (in ordinary examples) by its deli-
cate red or reddish-grey colour, and its occurrence in aggregations of soft,
pearly scales. Also by its intumescence and ready fusion in the blowpipe-
flame, or even in the flame of the Bunsen burner, and by the crimson coloration
which it imparts to this. In the spectroscope, the crimson Li-line and yellow
Na-line come out at once with great brilliancy, but the red K-line is generally
overpowered by the intensity of the lithium spectrum, unless this be cut off
by the intervention of a blue glass between the spectroscope and the flame.
The Boro-silicates of this Table include the dark, fusible Tourmalines,
represented essentially by Schorl, and the anorthic species, Axinite. These,
however, have no very close relations as minerals, beyond the presence in both
.of boracic acid, an exceptional component. The silica percentage is com-
248 BLOWPIPE PRACTICE.
paratively low, averaging 38 or 39 in Tourmaline, and about 44 in Axinite,
The boracic acid apparently replaces alumina.
Schorl may generally be distinguished by its jet-black colour and triangular
cross fracture. The crystals are sometimes simple three-sided prisms ; but
these are bevelled, in general, on their vertical edges — a combination of —
and V2 being thus formed — and they are usually terminated by the planes of
a rhombohedron (R) with polar angle, i.e., angle over a polar edge, of about
133° 30'. Frequently also the planes of a second rhombohedron ( - 2R) with
polar angle of about 103° or 103° 20', alternate with the latter ; and crystals
often shew dissimilar forms at their extremities : see the Note to TABLE XXIV.
Axinite is readily distinguished by its flattened, sharp-edged, anorthic
crystals (brown, violet, pinkish-grey, in colour, or sometimes green from inter-
mixed chlorite), and by the green coloration which it communicates -to the
blowpipe-flame during fusion. The crystals are essentially oblique rhomboidal
prisms with only the diagonally-opposite edges and angles replaced. The
prism-angle equals 135° 31' ; B on one prism-plane, 134° 45' ; and on the other
prism-face, 115° 38'.* The two prism- planes are vertically striated, i.e.,
parallel with their combination edges, whilst the B plane is striated trans-
versely.
The Garnet group is represented in this Table by the different varieties or
sub-species of Garnet (the infusible chrome-garnet Uwarowite [TABLE XXIV.]
excepted), and by the related species Vesuvian.
The specific name of Garnet includes a great number of related silicates of
regular crystallization and common formula — the latter, empirically, 3 HO,
11203, 3 SiO2. The RO represents CaO, MgO, MnO, FeO ; and the R203 equals
A1'203, Fe203, &c. The varieties which result from the preponderance of one
or the other of these isomorphous bases necessarily present different colours,
and, within certain limits, different degrees of specific gravity, t The colour
thus varies, as a rule, from light tints of red, yellow, and green, through deep-
red and olive-green into brown and black ; and, occasionally, colourless
examples are met with. The more common garnets are dark-red or red-
brown, and nearly or quite opaque. The average sp. gr. is about 3 '5 for the
lighter coloured varieties, and 3 '9 or 4'0 for the dark garnets, the limits lying
between 3 '15 and 4 "25 or 4 '3. The crystallization is comparatively uniform,
consisting essentially of the rhombic dodecahedron or of the trapezohedron
2-2, or of the two combined. In the trapezohedron, the angle over a long or
axial edge equals 131° 49'. In combination, the trapezohedron replaces the
edges of the dodecahedron, and thus presents a cruciform four-planed point-
*By most German crystallograpliers B is made the face of a tetarto-pyramid, P. The angles
given above are" those of Von Rath, but they fluctuate within 30 or 40 minutes in crystals from
different localities.
t This latter character, however, does not depend absolutely on composition, as regards
minerals generally. A striking instance is afforded by ordinary Iron Pyrites and Copper
Pyrites. The former, consisting of Fe 46'67, S 53'33, has an average sp. gr. of 5'0; whilst the
latter, with less sulphur (34 '9 , and with the heavier metal copper forming part of the base
(Cu 34 '6, Fe 30'5), shews a maximum density of only 4/3.
MINERAL TABLES : XXVI. 249
ment at each pole of the crystal. Occasionally also, the edges of the rhombic
dodecahedron are bevelled by the planes of the adamantoid 3-f or 4-f .
Vesuvian or Idocrase closely resembles Garnet in general composition, and
until recently the two were thought to present the same atomic constitution.
This is probably not the case, although the formula of Vesuvian is still doubtful.
But the two minerals apart from crystallization are evidently nearly allied.
The more common crystals of Vesuvian are composed of the two square prisms
V and V, striated longitudinally, and terminated by a square pyramid, P,
more or less deeply truncated at the apex by the basal form B. Frequently
the vertical edges of V are bevelled by the planes of an octagonal prism V2 or
V3 ; and the polar edges of the pyramid are replaced by a front-polar or front-
pyramid R Angular measurements are slightly variable, but average as
follows : P : P over polar edge 129° 29', over middle edge 74° 14' ; B : P
142° 53' '; P : Fover polar edge 141° 1', over middle edge 56° 8' j B : P 151° 56'.
For other characters, see the Table.
The Epidote Group is represented in the Table by Epidote, Zoizite, and
Allanite or Orthite. The latter in most examples is decomposed with gelati-
nization by hydrochloric acid, and is black and almost sub-metallic in aspect.
Commonly in columnar and fine-granular masses jjnore rarely in clino-rhombic
crystals, with V : V 70° 48' and 109° 12' ; V : V 125° 24' ; and B : V 115°.
This latter is also the cleavage-angle, but the cleavage is very indistinct.
Zoizite and Epidote are not decomposed by hydrochloric acid until after
fusion, when they also gelatinize. Zoizite is light- coloured, mostly grey or
greyish-white*, and chiefly in columnar masses. Its crystallization, long con-
sidered identical with that of Epidote, is now regarded as Rhombic, but
crystals are rare and more or less indistinctly formed. Epidote is usually dis-
tinctly coloured, the tints ranging from light yellowish-green to dark green,
brown, and black. Many examples are fibrous and acicular, and closely
resemble examples of pyroxene and arnphibole, and also schorl. From these,
however, Epidote is readily distinguished by its peculiar reaction'under the
blowpipe. In place of forming a single bead or fused globule, it swells up
into a cauliflower-like mass, the separate portions of whiten become rounded,
but cannot with ordinary blowing be brought into a bead, properly so called.
Crystals are of frequent occurrence. They are clino-rhombic, and practically
identical with those of Orthite, but are not easily made out by the unpractised
eye. In their conventional position, they form transversely elongated prisms,
the extension being in the direction of the ortho -diagonal or right-and-left
axis, with usually two (or several) inclined planes at the side. The horizon-
tally extended planes usually comprise the basal plane B, and the front-vertical
V, with interfacial angle (which is also the cleavage angle) of 1 15° 24'. In the
same zone with these planes, several intermediate planes (the faces of front or
ortho-polars) also frequently occur ; and in most cases the planes of this zone
are striated parallel with their combination- edges. The more common forms
of the zone are B (the chief cleavage-plane), V (the second cleavage-plane),
and P ; with consecutive interfacial angles of 115° 24' as stated above, 128° 18',
and 116° 18'. The two predominating planes at the lateral ends of the crystal
251J BLOWPIPE PRACTICE.
are sometimes the prism-planes V, with angles of 110° on adjacent faces, and
70° in front or over V, and 125° on V. In other crystals, these end planes are
those of the hemi-pyramid P, and they meet at an angle of 109° 35'. Both V
and P are also sometimes present together, meeting at angles of 150° 57' and
117° 40'. Twin combinations, with twin-face parallel to V, are of frequent
occurrence.
The so-called Iron Chrysolites are represented by Fayalite, Hyalosiderite,
and Lievrite or Ilvaite, the latter, only, of general occurrence. This species,
by its black colour and general aspect somewhat resembles Orthite. Like
Orthite also, it melts readily into a black magnetic glass, and is decomposed
with separation of gelatinous silica by hydrochloric acid. The crystallization
however is Rhombic, and the crystals are elongated vertically. In most
cases they are eight-sided prisms, composed of the two rhombic prisms V and
V2, terminated by the four planes of a rhombic pyramid P, the front polar
edges of which are replaced by a plane of the form P. The chief angles are as
follows : V : V 112° 38' ; V2 : V2 106° 15' ; P : P, over front edge_or over P3
117° 30' ; over side edge 139° 30' ; over middle edge 77° 12' ; P : P, over sum-
mit, 11 2° 49'. The prisms, in general, shew strong vertical striae, indicating
additional prismatic forms, V£, &c. ; and crystals thus affected often become
more or less cylindrical, and pass into columnar masses.
The Pyroxene series comprises a group of species and sub-species (essentially
bisilicates of RO, typically MgO, FeO, CaO) in which the crystallization is
either Clino-Rhombic or Rhombic, with the chief prism-angle and cleavage-
attgle approximating to 87° (or its supplement 93°). The Rhombic species
comprise Enstatite, with Bronzite and Hypersthene. The typical Clino-
Rhombic forms, in which, as in the Rhombic group, alumina is either absent
or only subordinately present, include Pyroxene proper, with Acmite and
other rarer species ( Jeffersonite, &c. ) ; and also the manganese species,
Rhodonite, and the more or less aberrant Wollastonite, the latter a purely
calcareous species differing essentially from the ordinary pyroxenes by being
readily decomposed, with separation of gelatinous silica, in hydrochloric acid.
The lithia-holding and aluminous Spodumeiie or Triphane is also commonly
referred to the Pyroxene group from its cleavage-angle and lately determined
crystallization ; but its composition (Li20 4*5 to 6 "5, APO3 25 '3 to 29, SiO2 63
to 66) and its general aspect, are more feldspathic than augitic. The prism-
angle (and corresponding cleavage-angle) V : V, scarcely differs from the
principal cleavage-angle in Albite. Its distinctive characters, and those of the
other minerals of the group, are given sufficiently in the Table, but some
additional remarks on the commonly occurring species Pyroxene are here
appended. This species is commonly subdivided into Non-aluminous ' and
Aluminous Pyroxene. The non-aluminous pyroxenes (apart from the ferrugi-
nous sub-species Hedenbergite) are chiefly of a light colour, and the aluminous
varieties, mostly (though not exclusively) deep-green or black, and more or
less ferruginous ; but even in these, the alumina is always under 10, and
generally under 7, per cent. The old name of Diopside may serve conveniently
MINERAL TABLES: — XXVI. 251
to include all the light-coloured non-aluminous pyroxenes (Malacolite, Alalite,
&c.), and that of Augite to denote the dark and generally aluminous varieties.
In both diopside and augite the crystals are prismatic and essentially eight-
sided, or (as regards these prismatic planes) made up of the four planes of the
rhombic prism V, truncated on its obtuse vertical edges by the two planes of
the Front- Vertical V, and on its acute edges by the Side- Vertical or Clino-
Vertical V. The prism-angle in front equals 87° 6' ; V on V of course equals
90° ; and V on V7 133° 33'. But apart from these vertical planes, Pyroxene
crystals present three more or less distinct types. In one, common to both
light and dark varieties, the crystals are simply 8-sided prisms terminated by
the basal plane, * with B on V equal to 105° 30'. These crystals are sometimes
flattened parallel to V (the ortho-pinakoid) ; but in general they are remark-
ably symmetrical, and as the pinakoids or Front and Side Verticals, V and V,
which meet at right angles, frequently preponderate, this type of crystal looks
remarkably like a square prism with truncated vertical edges. In the second
type, especially characteristic of augite, proper, the crystals are almost invari-
ably flattened parallel with V, and are surmounted by the two planes of the
clinodome or side-polar P, meeting over the summit at an angle of 120° 48'. "\
In this type, the base is also occasionally, but only subordinately, present,
together with other slightly developed polar forms ; and its crystals are often
twinned parallel with V. The crystals are then terminated by four planes,
and shew re-entering angles at one extremity. In the third type, the crystals
are largely terminated by the planes of a hemi-pyramid, with angle over front
polar edge of 95° 48', a second hemi-pyramid, with front angle of 131° 30'',
often appearing at the lower extremity. Other combinations occur, but are
comparatively rare.
The Amphiboles form a parallel series with the Pyroxenes, and like the
latter are essentially bisilicates of CaO and MgO, with part of these bases
replaced in dark varieties by FeO ; and with APO3 (5 to 15 per cent. ) frequently
replacing a portion of the silica, the latter in non-aluminous amphiboles vary-
ing from about 55 to 59 per cent., and in aluminous varieties from 39 to 49
per cent. Small amounts of fluorine and alcalies are also commonly present,
especially in the darker amphiboles ; and magnesia always exceeds lime in the
base, whereas in the pyroxenes the lime predominates. Corresponding varieties
shew in amphibole a slightly lower sp. gr. than in pyroxene ; but, practically,
* By German and many_other crystallographers this is not regarded as the base, but as an
orthodome or front-polar P. By making it the base, however, the two sloping planes by which
the common augite crystals are always terminated, become clinodomes or side-polar planes P,
in place of being the planes of a hemi-pyramid P; and in that manner, as pointed out by VON
RATH, the correspondence between pyroxene and amphibole crystals is rendered much more
apparent. This view has been always held by French crystallographers, and is recommended
by its greater simplicity. It was departed from, apparently, in the first instance by German
crystallographers in order to obtain an imaginary Grundform or triaxial pyramid.
t See the preceding foot note. These terminal planes are regarded by most German crystailo-
graphers as the planes of a hemi-pyramid, P,
252 BLOWPIPE PRACTICE.
the two species can only be distinguished by their crystallization and cleavage-
angles. In Amphibole proper, two leading varieties' or sub-species may be
recognized. Tremolite or Grammatite, including all the white, grey, and pale-
green amphiboles ; and Hornblende, including the deep-green, dark-brown and
black kinds. These are connected by the variety known as Actynolite, which
presents a more or less bright-green colour, and usually occurs in fibrous
masses and long prismatic crystals and aggregations. These forms are also
generally presented by Tremolite ; whilst Hornblende is usually in dark-green
lamellar or granular masses, or in thick crystals (commonly known as Basaltic
Hornblende) of a dark-brown or black colour. The System, as in Pyroxene,
is Clino-Hhombic, and viewed generally, amphibole crystals present three
leading types. The first and simplest type is comparatively rare. It consists
of an eight-sided -prism composed of the vertical forms V, V, and V, terminated
by a large basal plane ; and it thus represents the simple Pyroxene type
described under that species. V : V= 124° 30' ; V : V 1 17° 15' ; B : V 104° 50'.
A second and much commoner type consists of a six-sided prism composed of
the rhombic prism V (with angle as above) truncated on its acute vertical
edges by the form V, and terminated by two nearly flat side-polar planes P,
meeting at an angle of 148° 16'. Sometimes, also, the base, in the form of a
narrow plane, replaces the common edge of these terminal planes ; and
occasionally the prism is eight-sided from the presence of V ; but this front-
vertical form, so characteristic of Pyroxene crystals, is comparatively rare in
Amphibole. The third type, exhibited especially by the so-called Basaltic
/
Hornblende, consists of a six-sided prism, composed of V and V (with planes
of practically equal width), surmounted by three rhombiform planes, consist-
ing of two planes of a hemi-pyramid P, and the basal plane B — these three
terminal planes being also in general of equal or nearly equal size. A
marked pseudo-hexagonal aspect is thus imparted to the crystal. P : P
148° 30', P : B 145° 35'. Other polar forms are sometimes subordinately pre-
sent ; and the crystals of this type are frequently twinned parallel to the
position of the front-vertical V. In these twins there is no re-entering angle,
but the four planes of the hemi-pyramid P are brought together at one end of
the crystal, and the two B planes at the other. The iuterfacial angle of the
Basal planes, thus brought together, equals 150° 20'.
The Scapolites are essentially lime-alumina silicates of Tetragonal crystalli-
zation. They have been separated into various species or sub-species, but a]l
may fairly be referred to a single representative, Scapolite proper or Wernerite.
In this species, the crystals consist commonly of combinations of the two
square prisms V and V, forming an eight-sided prism, terminated by the four
planes of the pyramid P, or by those of P and P, the common summit of these
being frequently truncated by the basal form B. The angles fluctuate some-
what in different varieties, but average_as follows^ Bj^P 148° 9' ; P : P over
polar edge 136° 11' ; P : V 121° 51' ; B : P~ 156° 14' ; P : P over polar edge 147°.
In addition to these forms, many crystals shew an octagonal prism V2 (slightly
MINERAL TABLES : XXVI. 253
developed), and an octagonal pyramid 3P3, but these are usually in a hemi-
hedral condition. Many crystals, again, are much distorted from inequalities
in the size of corresponding planes. Apart from its crystallization, Wernerite
is distinguished from light- coloured Pyroxenes and Amphiboles by its lower
specific gravity (2 '6 to 2 '8, in place of 2 '9 to 3 '4), and by its partial decom-
position in hydrochloric acid. From the Feldspars it differs essentially by its
want of sharply- defined, smooth and lustrous cleavage-planes, and by its ready
fusion. The more typical feldspars, moreover, Orthoclase and Albite, are not
attacked by hydrochloric acid.
The Feldspars are essentially aluminous silicates of potash, soda, or lime,
characterized by the general absence of iron oxides and magnesia, by their
light coloration, their non-fibrous, cleavable structure, the latter an especially
salient character, and by their clino-rhombic or triclinic (anorthic) crystalli-
zation. As a rule, they are difficultly fusible, and the lime species only are
decomposed by acid. In the more typical or alcaline feldspars, the amount of
silica exceeds 60 per cent. It is now very generally thought that three species
only of feldspar should be admitted, viz. : the potassic species Orthoclase, the
soda species Albite, and the lime species Anorthite, the other so-called species
being regarded as isomorphous mixtures or combinations of these. This view
is probably correct, but in the present state of our knowledge it seems neces-
sary to recognize (as in the Table) the following compounds as constituting
distinct feldspathic types : The potash feldspars Orthoclase and Microcline ;
the baryto-potassic feldspar Hyalophane ; the soda feldspar A Ibite ; the soda -
lime feldspar Oligoclase (including Andesine) ; the lime-soda feldspar Labra-
dorite ; and the lime feldspar Anorthite. The more distinctive characters of
these are given fully in the Table ; but some additional remarks on the
crystallization of the two more important species Orthoclase and Albite are
here appended.
Orthoclase crystals fall under three comparatively distinct types. The
crystals of the first or simplest type are short rhombic-prisms terminated by
two sloping planes. The latter are frequently'of nearly similar size and shape,
but consist of the base, B, and a hemi-orthodome or ortho-polar P, of course
in alternate positions. V : V 118° 47' ; B : P 129° 43' ; B : V 112° 13' ; P : V
110° 41'. P is often transversely striated, and is sometimos much larger than
B, in which case its planes resemble the V planes -in shape, and the crystal
has much the aspect of a truncated rhombohedron. Occasionally, the side-
vertical V is also present. This type frequently occurs in twin forms, with
twin-face,* a face of B. It might be termed the Adularia or St. Gothard
type. Its crystals are in general more or less translucent, and are always in
druses or attached to the sides of clefts and cavities of the rocks in which they
occur. In the se^ oud or Baveno type, the crystals are usually six-sided prisms,
composed of four V planes and the two planes of the side or clino- vertical V,
terminated by the basal plane and a second ortho-dome or ortho-polar 2P.
* Throughout these notes, the terra "twin-face" always denotes the face or plane of junction
of the united crystals.
254 BLOWPIPE PRACTICE.
These crystals, as a rule, are greatly elongated in the direction of the clino-
diagonal, and thus the two B planes and the two V planes become drawn out
backwards and upwards, so as to mask the true symmetry of the crystal to
an unpractised eye. V : V and B : V, as above ; V : 2P 134° 20' ; B : 2P
99° 38' ; B : V 90°. The cleavage is parallel to the latter planes. Very fre-
quently the edges between B and V are replaced by the side-polar or clino-
dome 2P, the planes of the latter inclining on B and V at angles respectively
of 135° 4' and 134° 56'. Occasionally also, the vertical edges between V and
/ /
V are replaced by the planes of the prism V3. Crystals of this type occur very
commonly in twins, with the twin-face a plane of the side-polar or clino-dome
2P. In these crystals, consequently, two long B planes, and two long V
planes, come together, and the crystals are rectangular in aspect. In other
twins — with marked re-entering angle — the basal plane is the twin-face or
plane of junction. These crystals are sometimes translucent, but are com-
monly opaque, and are often rough or dull on their external surfaces. Crys-
tals of the third or Carlsbad type possess the same forms as those of the pre-
ceding type, but present a very different aspect from the predominance of the
side- vertical planes V, and the apparent flattening of the crystals parallel with
these. The elongation moreover is essentially vertical. Simple crystals are
much less common than interpenetrating twins, with twin-face parallel with V.
These crystals are always imbedded, and they are commonly quite opaque and
more or less rough and dull. Very often they are partially altered into
Kaolin, and sometimes into impure Calcite, without change of form ; and in
Cornwall, tin-stone pseudomorphs have assumed their shape. A fourth type
is presented, according to Gustav Rose, by the orthoclase twins from the
syenite of southern Norway, in which the form V fails, and the crystals are
united parallel to the ortho-vertical V.
In Albite, simple crystals are of rare occurrence. Crystals which appear to
be simple, are in most cases really compound, as shewn by the striation of the
basal plane. One of the more common combinations consists of a six-sided
prism composed of the three forms V, (V), and V, terminated by three other
forms, the base B, a front polar (P), an I a tetarto-pyramid (P) : each of these
six forms, of course, consisting of a pair of opposite planes only. When the
X
crystal is in position, B appears at the top in front, and (P) and (P) at the
back ; these positions being necessarily reversed as regards the bottom of the
crystal. V : (V) 120° 47' ; B : (P) 52° 17' and 127° 43' ; B : V 86° 24' and
93° 36' (= the cleavage angles) ; B : V 110° 50' ; B : (V) 114* 42. The side-
vertical planes V commonly preponderate and impart a flattened appearance
/
to most crystals. In the more common twins, two B planes, two V planes,
and two (P) planes come together. The re-entering angle between B and B
MINERAL TABLES : — XXVI. 255
equals 172° 48', and these planes are delicately or strongly striated. Double
or multiple twins of this character, with two B planes and two (P) planes
alternating at both extremities of the crystal, are not uncommon.
In the variety of Albite known as Pericline the crystals are more or less
elongated in a transverse or right-and-left direction, but the interfacial angles
\
are practically identical with those given above. The forms B and (P) pre-
/
dominate, and the short, side-vertical planes V are strongly striated ; but the
striae arise, here, from an oscillation between the latter form and another ver-
tical prism V3, the planes of which occasionally replace the combination edges
N
of V and V, or V and (V). In the twinned Periclines, the plane of junction
is parallel to the base.
[236]
TABLE XXVII.
[Lustre nou-metallic. Slowly attacked or only in part dissolved, BB, by
phosphor-salt. Fusible. Yielding water on ignition].
A. — Fusion-product, magnetic.*
AW DECOMPOSED WITH GELATINIZATION BY HYDROCHLORIC ACID.
t In masses of essentially leafy or scaly structure, or in crystals with
marked basal cleavage. Hardness less than that of calcite.
CRONSTEDITE: MgO, MnO, FeO, Fe2O3, SiO2, H20 (10 to 12 per
cent.). Henri-Hex. ; crystals very small, often acicular, mostly very
acute rhombohedrons and scalenohedrons with basal plane ; cleavage
parallel to the latter ; in thin leaves somewhat flexible ; also in radi-
ated-fibrous examples. H 2*5 ; G 3 -3-3 -3 ; black ; streak, dark-green.
Fusible with intumescence into a black magnetic bead. Sideroschi-
zolite is identical or closely related. In both, the crystal-planes
shew a strong tendency to curvature, and in Cronstedite the R planes
are longitudinally striated.
YOIGTITE (Altered Biotite?) : CaO, MgO, FeO, Fe203, A1203, SiO2,
H20 (9 per cent.). In green or dark-brown scaly and foliated ex-
amples, resembling an ordinary dark-coloured mica. Fusible into a
black, more or less magnetic bead.
THURINGITE : MgO, MnO, FeO, Fe203, A1203, SiO2, H2O (10 to
12 per cent.). In dark-green, scaly -granular and micaceous masses,
with greyish-green streak and pearly lustre. H 2-0-2-5; G 3-1-3-2.
Fusible into a black, magnetic bead. Owenite is identical or closely
related.
METACHLORITE : FeO, A1203, SiO2, H20. In dark-green, radiated,
leafy masses, resembling ordinary Chlorite, but differing by its larger
percentage of FeO, and by gelatinizing in hydrochloric acid.
f f Occurring in earthy or uncrystalline masses.
CHAMOISITE (Ohamosite) : FeO, A12O3, SiO2, H2O, often mixed
with calcite, &c. In dark-green or greenish-black, fine-granular,
*The minerals of this subdivision are for the greater part of more or less indefinite compo-
sition. Very few can be ranked, properly, as distinct species. In most cases, therefore, only
their essential components are stated in the Table. As a rule, lime is not present normally in
these minerals, but many, after prolonged ignition, shew a calcium spectrum from the presence
of intermixed calcite.
MINERAL TABLES : — XXVII. 257
oolitic, or earthy masses ; H 2-0-3-0 ; G 3-0-34. Easily fusible into
a magnetic bead. Gelatinizes in hydrochloric acid.
LILLITE: FeO, Fe203, SiO2, IPO (about 11 per cent.). In black-
ish-green, earthy rounded masses ; H 2-9; G 3'04. BB, fuses with
difficulty into a dark magnetic slag. Gelatinizes in hydrochloric
acid.
PALAGONITE : CaO, MgO, APO3, Fe2O3, SiO7, H2O. In granular
masses of a yellow or dark-brown colour and vitreo-resinous lustre ;
streak, dull yellow; H 3-0-5-0; G 2-4-2-6. Easily fusible with in-
tumescence into a more or less magnetic bead. Rapidly decomposed
by hydrochloric acid, with separation of gelatinous silica, as regards
most examples.
f f f In distinct crystals or in fibrous and columnar masses which
scratch glass readily.
ILVAITE; ORTHITE : See TABLE XXVI. Some examples, only,,
evolve traces of water on ignition.
A*.- DECOMPOSED BY HYDROCHLORIC ACID, WITH SEPARATION OF SCALY
OR GRANULAR SILICA.
t In leafy or scaly masses, or in tabular or prismatic crystals with
marked basal cleavage.
CHLORITE (Aphrosiderite and other essentially ferruginous vari-
eties): MgO, FeO, Fe2O3, APO3, SiO2, H2O (about 9 to 12 per cent.)..
In tabular (Hexagonal) crystals, and in foliated and fine-scaly masses,,
of a dark or bright-greon colour; H 1-1-5 ; G 2'75-2'95. BB, melts.
as a rule on the edges and surface, only, into a dark magnetic slag.
Strigovite is closely similar in general characters ; but its sp. gr. i&
slightly lower, 2-59, and its water percentage equals 14-80 according
to "Websky's analysis. Delessite is another dark-green chloritic min-
eral, occurring in scaly and fine-fibrous masses and coatings in amyg-
daloidal traps.
ASTROPHYLLITE (Titaniferous Mica): In golden or bronze-yellow
foliated masses, often radiately grouped, and in tabular Clino-Rhom-
bic crystals ; H 3 -5. Most examples yield only traces of water on
moderate ignition. See TABLE XXVI., page 228.
PYROSMALITE: Essential components — MnO, FeO, SiO2, ITO
(about 8 percent.), Cl. Hexagonal : crystals mostly six-sided prisms
or tables with strongly-marked basal cleavage ; occurs also in granu-
18
258 BLOWPIPE PRACTICE.
lar masses ; brown, dark-green, with metallic-pearly lustre on cleav-
age plane; H 4-0-4-5; G 3-0-3-2. In bulb-tube yields water, and
on stronger ignition, yellow drops of ferrous chloride. BB, fuses
easily into a steel-grey or black magnetic globule.
f f In granular, fibrous, or earthy masses.
PALAGONITE : In granular, vitreo-resinous masses, of a yellow or
brown colour with dull-yellow streak. Commonly gelatinizes in
hydrochloric acid, but some examples are decomposed without gela-
tinization. See above, page 257.
DELESSITE : In dark-green scaly and short-fibrous masses and coat-
ings in amygdaloidal trap. See above, under Chlorite.
ANTHOSIDERITE : Fe2O3, SiO2, H2O (about 3-6 per cent.). In
tough, fibrous masses of ochre-yellow or brown colour, associated
with magnetic iron ore. H 6*5 ; G about 3'0. BB fuses with diffi-
culty to a grey magnetic slag.
XYLOTILE (Mountain Wood, &c.): MgO, Fe2O, SiO2, H2O (about
10 per cent.). In light-brown or dark-brown fibrous or ligniform
masses ; H 1-5-2-5 ; G 1-5-2-6, commonly about 2-2. Some examples
melt, BB, quite easily, others with difficulty, to a more or less mag-
netic bead. Mountain Cork is a related substance ; also Xylite ;
but, in all, the composition is indefinite. Some varieties do not give
BB, a magnetic product. Others are scarcely attacked by hydro-
chloric acid,
HISINGERITE (Thraulite) : Essential components — FeO, Fe203, SiO2,
HaO (19 to 22 per cent.), with small amounts of MgO, A12O3, &c.
In rounded masses with rough surface and compact structure, con-
choidal in fracture, and pitch-black colour, with brown or greenish
streak ; H 3 -0-4-0 ; brittle ; G 2-6-3-1 ; BB melts difficultly (in some
cases on the edges only) into a grey or dark magnetic slag.
MELANOLITE : Na2O, FeO, A12O3, Fe203, SiO2, EUO (about 10 per
cent.). In black, sub-fibrous coatings of waxy lustre and somewhat
greasy feel ; H 1'5-2'0 ; G 2'7-2'9. Easily fusible into a black mag-
netic globule.
SELADONITE (Green Earth) : K20, MgO, FeO, A1O3, SiOa, H2O,
mixed with CaOCO2, <fcc. In earthy or compact masses and coatings in
amygdaloidal traps, and also frequently in pseudomorphs after augite.
Green of various shades ; somewhat shining in the streak ; H 1 -0-2-0 ;
MINERAL TABLES : — XXVII. 259
O 2-8-2*9. BB, melt's into a black magnetic bead. In hydrochloric
acid loses its colour, and is slowly decomposed with separation of
fine-granular silica. Glauconite or Green-Sand, in disseminated par-
ticles and grains in cretaceous and other strata, is of generally similar
character. Both substances, when ignited in the Bunsen-flame, shew
the red K-line, in the spectroscope, very distinctly.
A3. -INSOLUBLE IN HYDROCHLORIC ACID, OR SCARCELY ATTACKED BY
THAT REAGENT.
f In masses or crystals of leafy or scaly structure with strongly-marked
cleavage in one direction.
(Fusible in thin pieces}.
FERRUGINOUS MICAS (BIOTITE, &c.) : Yield traces of water in some
examples, only; as a rule, fuse merely on the edges. See TABLE XXY.
(More or less brittle. Hardness insufficient to scratch glass).
STILPNOMELANE : Essential components — MgO, FeO, A12O3, SiO*,
H20 (about 9 pfer cent.). In dark-green or greenish-black radio-
foliated masses or small scaly particles. H 3-0-3-5 j G 2-8-3-4.
Fusible (in some cases readily, in others slowly) into a magnetic slag
or globule. Scarcely attacked by acids.
(Hardness sufficient to scratch glass slightly).
CHLORITOID: Average composition — MgO 3-0, FeO 27-0, APO*
39-0, SiO2 26, H20 7-0. In dark or blackish-green, foliated and
scaly-granular masses, the folise more or less curved and brittle.
H 5-5 ; G 3-5-3-6. BB, slowly fusible (often on the edges only)
into a black magnetic slag. Slightly attacked by hydrochloric, but
readily decomposed by sulphuric acid. Sismondine (blackish-green),
and Masonite (dark greenish-grey) are apparently identical. Ottre-
lite (greenish -grey to greenish-black, in small six-sided tables with
rounded angles, in certain clay slates) is also closely related. It
gives, BB, with carb. soda a strong manganese-reaction.
f f In fibrous masses.
(Easily fusible).
KROKYDOLITE (Crocidolite) : Na2O, MgO, FeO, SK>, H20 (2:5
to 5 per cent.). In deep-blue or lavender-blue fibrous masses, the
fibres tough and flexible. H 3-0-4 -0 ; G 3-2-3-3. Easily fusible into
a black magnetic globule.
260 BLOWPIPE PRACTICE.
KIRWANITE; CaO, FeO, APO3, SiO2, HzO (about 4 per cent.).
In opaque dark-green nodular masses of radiated-fibrous structure.
H 2-0 ; G 2-9. BB black ens-, and melts.
(Fusible on edges only.)
XYLITE : CaO, MgO, Fe203, SiO2, H20 (47 per cent.), with small
(accidental V) amount of CuO. In opaque nut-brown, fibrous or
ligniform masses. H 3'0 ; G 2-93. Fusible on the edges only. Dis-
tinguished from Xylotile or Mountain Wood, proper, by its resist-
ance to acids. It differs also from the latter mineral by containing
(according to Hermann's analysis) a certain amount of lime.
Iff In more or less earthy or compact masses.
. SORDAWALITE : MgO, FeO (or Fe203), APO3, SiO2, H20, with inter-
mixed ferrous phosphate, &c. In black or dark-green coatings and
earthy masses, weathering brown. H 4*0-4-5 (?); G 2-6; fusible
into a black magnetic globule. Partially decomposed by hydro-
chloric acid. Hitherto, from Finland only.
CHLOROPHJSITE : MgO, FeO, SiO2, H2O (about 42 per cent.). In
green or brownish-green amygdaloidal masses in trappean rocks.
Weathers brown and black. H l'O-2'O; G about 2-0. BB, forms
a black magnetic slag or globule. Distinguished from Delessite,
Lillite, Chamoisite, &c., by its resistance to hydrochloric acid, and
by the large amount of water which it yields on ignition. Nigrescite,
a green amygdaloidal mineral, blackening on exposure, is identical
or closely related.
B. — Fusion-product, non-magnetic.
BV— FUSIBLE ON THE EDGES OR IN FINE SCALES OR SPLINTERS ONLY; BUT
EXFOLIATING AND CURLING UP, IN SOME CASES, ON IGNITION.
f Micaceous or scaly minerals.
( Water under 5 '5 per cent. In bulb-tube little more than traces evolved. )
MUSCOVITE (Ordinary or Potash Mica): Elastic in thin leaves.
Not decomposed by sulphuric acid. See TABLE XXV., page 213.
DAMOURITE : KX) 11-20, APO3 37'85, SiO2 45-22, H2O 5-25. In
yellowish-white pearly scales and foliated masses, associated (as
regards known localities) with Staurolite and Cyanite, or with
Corundum. H 1-5-2-5; G 2-8. BB exfoliates, and melts on edges.
Decomposed, with separation of silica scales, by sulphuric acid.
MINERAL TABLES: — xxvii. 261
Margarodite and Sericite are closely allied micaceous substances, ap-
parently altered Muscovite, with variable amounts of water. All
shew the red K-line in the spectroscope very distinctly.
PARAGONITE (Hydrous Soda-Mica): NaK), K2O, A12O*, SiO2, H'O
(2 -5 to 4'5 per cent.). In scaly or schistose masses of a yellowish-
white, pale-grey, or light-green colour, and pearly lustre, H 2-0-
3'0; G 2 -7 9. Fusible on the edges into a white enamel; decom-
posed by sulphuric acid. Pregrattite, distinguished by marked ex-
foliation BB, is closely related,
OELLACHERITE (Hydrous Barium-Mica) : K20, Na20, SrO, BaO,
CaO, MgO, APO, SiO2, H2O (about 4 or 4'5 per cent.). In white or
pale-green scaly masses of pearly lustre, H 1'5-3*0 (?); G 2-8 2 '9.
Fusible into a white enamel. Should be readily distinguished by its
spectroscopic reactions, but the author has not been able to procure
a specimen for examination,
PHLOGOPITE (Potassic-Magnesian Mica) : In golden-brown, mica-
ceous crystals and masses. Decomposed by sulphuric acid. See
TABLE XXV., page 213.
COOKEITE : A hydrous mica, giving marked lithium reaction BB,
or in spectroscope. Forms red or reddish-grey scaly aggregations.
Probably altered Lepidolite.
RUBELLANE : Na*O, K*O, MgO, Fe203, A12O3, SiO2, H20. In red
or brownish-red hexagonal tables with pearly lustre on cleavage
plane. H about 2-5 ; somewhat brittle. BB, melts (in some cases
on edges only) into a dark ferruginous glass. Regarded as an altered
Mica. Occurs in certain trachytes and other volcanic rocks. Hel-
vetane (copper-red, yellow, green) is closely related.
MABGARITE (Pearl Mica) : In white or light-coloured scaly and
foliated masses with strong pearly lustre. Fusible on edges, only,
but in some cases with slight bubbling. Moistened with hydro-
chloric acid, shews momentary red and green Ca-lines in spectroscope.
See TABLE XXV., page 215.
TALC : MgO, SiO2, with small amount of basic water. In white,
light-green or other foliated or scaly examples, with pearly lustre.
H 1 '0 ; very sectile, flexible, and soapy to the touch. BB, exfoliates,
but melts on thin edges only. Evolves merely traces of water in the
bulb-tube. With Co-solution becomes flesh-red. See TABLE
page 214.
262 BLOWPIPE PRACTICE.
(Water, 5 '6 to 14 per cent. : evolved in marked quantity in bulb-tube.)
PYROPHYLLITE : APO3, SiO2, IPO, with traces of MgO, &c. In
light-green or greenish- white radio-foliated and scaly masses. H 1 *0.
BB, exfoliates and curls up, but remains practically unfused. Be-
comes blue by ignition with Co-solution. Belongs properly to Table
XXV.: see page 214. See also Nacrite or Pholerite, page 219.
YERMICULITE : MgO, FeO, APO3, SiO2, H2O, with traces of CaO,
K20, &c. In scaly and coarsely-foliated examples and six-sided
micaceous tables of a yellowish -brown, yellow or green colour. HI -0-
1-5; G 2-2-2-4; slightly flexible in thin leaves. BB, expands and
curls up greatly, and melts subsequently to a white or greyish en-
amel. According to Prof. Cooke, should form three species : Jef-
ferisite, Culsageeite, Hallite.
CHLORITE (Pennine); and RIPIDOLITE or CLINOCHLORE : In green,
scaly or foliated masses and micaceous crystals. As a rule, fusible
on the edges only, in many cases into a black, slightly magnetic en-
amel. Belong properly to Table XXY. : see page 213.
f f Minerals of compact, fibrous, or other non-micaceous structure.
More or less distinctly sectile*
(Assume a blue colour after ignition with Co-solution.)
AGALMATOLITE : Massive, fine-granular, or compact in structure ;
white, greyish, greenish, &c. The substance of many Chinese " Figure-
stones." Fusible on thin edges, only. See page 219, TABLE XXY.
PINITE, FAHLUNITE, PYRARGILLITE ; WEISSITE ; IBERITE ; ESMARK-
ITE; BONSDORFFITE : In more or less dull and opaque crystals —
essentially six-sided, eight-sided or twelve-sided prisms — of a greyish-
white, grey, brown, green or dull-bluish colour. Fusible on the edges
only. See page 220, TABLE XXY.
KILLINITE : K20, FeO, APO3, SiO2, H'O (about 9 or 10 per cent.,
or less in some cases). ' Chiefly in greenish-grey or brownish-yellow
columnar or broad-prismatic aggregations, translucent in thin pieces.
H 3-0-4-0; G about 2-7. BB, expands somewhat, and melts slowly
(in some cases on the edges and surface only) into a white or greyish
enamel. Decomposed, in powder, by sulphuric acid.
SCHR^ETTERITE (Hydrargillite (?) mixed with a lime or other sili-
* The minerals of this section are fusible, as a rule, upon the edges only. They belong pro-
perly, therefore, to TABLE XXV. See pages 219-222.
MINERAL TABLES : XXVII. 263
cate, traces of copper sulphate, &c. Yields on ignition from 36 to
41 per cent, water). In earthy and botryoidal masses, coatings, &c.,
of a green, pale-yellow, grey, or brownish colour, with more or less
conchoidal fracture. H 3'0-4'0 ; G about 2. BB, whitens, and
fuses slowly (often on edges only) into a white or light-grey enamel-
Decomposed (with gelatinization, according to .Fischer) by hydro-
chloric acid,
PYKNOTROPE : K20, MgO, APOS, SiO*, H20 (about 7 or 8 per
cent.). In greyish- white, pale-greenish, or brownish-red, coarse-gram
lar masses, with cleavage in two directions at right-angles. H 2'0-
3-0 ; G 2-6-2-72. BB, fusible only in thin splinters or on the edges.
Associated with serpentine.
(Assume a flesh-red colour by ignition with Co-solution, or do not, othervnty*
become blue).* *% ftf*
STEATITE (Compact or Granular Talc): In masses and pseudb-^
morphous crystals of a white, grey, greenish or other colour, often
mottled. Yery sectile ; yields very little water in bulb-tube, but
blackens more or less. BB, hardens, and fuses on thin edges. See
page 222.
SERPENTINE : Forms compact, fine-granular, or other masses, of a
green, red-brown, yellowish-grey, or variegated colour. In bulb-tube,
yields about 12 or 13 per cent, water. Fusible on thin edges Only.
See page 221, TABLE XXV.
ORYSOLITE (Fibrous Serpentine) : In silky, parallel-fibrous masses
of a yellowish-white or green colour, the fibres easily separable.
Melts at the point of a fine fibre into a white or greyish enamel. See
page 221, TABLE XXV.
MEERSCHAUM (Sepiolite) : In fine-granular or compact masses of a
white or pale yellowish colour, adherent to the tongue. BB, hardens,
but fuses on thin edges only. See page 221, TABLE XXV.
t Not sectile. Hardness sufficient to scratch glass.
POLLUX : In translucent, camphor-like masses and small crystals
(combinations of cube and trapezohedron 2-2). Yields traces only
of water in bulb-tube, and fuses only, BB, on thinnest edges. See
page 203, TABLE XXIV.
* In the bulb-tube, all blacken on evolving water.
264 BLOWPIPE PRACTICE.
B«. -FUSIBLE WITHOUT MARKED BUBBLING OR PREVIOUS INTUMESCENCE.
f Insoluble in hydrochloric acid.
DIALLAGE (Schistose and more or less altered Pyroxene) : In foliated
or sub-foliated masses of a greyish-green or greenish-brown colour and
metallic pearly lustre. Yields often merely traces of water : in no
case more than 3 or 4 per cent. See page 242, TABLE XXVI.
t-t Decomposed, by hydrochloric acid, with production of chlorine fumes.
(BB, with carb. soda, strong Mn-reaction.)
KCIPSTEINITE : MgO, MnO, Mn2O3, Fe2Os, SiO2, H20 (9 per cent.).
In amorphous masses of a brown or brownish-grey colour, with
reddish-brown streak; H 5*0 j G 3-5. Fusible into a dark slag.
t f t Decomposed, with or without gelatinization, by hydrochloric acid.
(BB, with borax, a chrome-green glass. )
PYROSCLERITE : MgO, FeO, APO3, (VO3 (1-43 per cent.), SiO2,
H2O (11 per cent.), von Kobell. In cleavable masses, indicating
Rhombic crystallization ; in thin pieces somewhat flexible ; H 3'0 ;
G 2 '7-2 -8; green of various shades, with pearly lustre on cleavage-
planes. Fusible quietly^ or with slight bubbling only, into a greenish-
grey enamel. Hitherto, from Elba only.
(In spectroscope, marked Ba-reaction when moistened with hydrochloric acid.)
HARMOTOME: K2O 3*3, BaO 20, A12O8 15-7, SiO2 46, H2O 15.
Rhombic (?) : commonly in groups of small, cruciform crystals, with
calcite, &c., in trap amygdaloids. Generally colourless, otherwise
white, grey, reddish, brown, &c<; H 4'5 -; G 2 -4-2 -5. Fuses quietly,
with pale-green coloration of the flame-border. Decomposed by
hydrochloric acid, with separation of fine-granular silica. See Note
at end of Table.
EDINGTONITE : BaO 26-84, A12O8 22-63, SiO2 36-98, H2O 12-46,
Heddle, Tetragonal; crystals, mostly, small square prisms with
hemihedral polar planes; greyish-white, pale-red; H 4-0-4-5 ; G 2 -7.
Gelatinizes in hydrochloric acid. Hitherto, from Scotland only','
accompanying harmotome, analcime, calcite, &c.
MINERAL TABLES :— XXVII. 265
(In spectroscope, marked Ca-reaction when moistened, after ignition, with hydro-
chloric acid.*)
PECTOLITE : Na2O, CaO, APO3, SiO2, H2O. Clino-Rh. ; but com-
monly in cleavable fibrous or sub-fibrous masses, with cleavage angle
of 95° 23' ( = B : Y). Colourless, or greyish or pale greenish- white,
often opaque and more or less earthy from alteration. H (in un-
weathered examples) 5-0; G- 2-74-2-88. Fuses quietly. Yields as a
I'ule only 2 or 3 per cent, water on ignition. Decomposed without
gelatinization by hydrochloric acid, but gelatinizes after fusion.
CHALILITE: Na2O, CaO, MgO, APO3, Fe2O3, SiO*, H*O (about 16
per cent.). Reddish -brown, massive; H 4-5 ; G 2*25. An imperfectly-
known mineral, hitherto from Antrim only.
ANALCIME ; NATROLITE : Normally lime free, but some examples
of exceptional occurrence shew momentary Ca-lines in spectroscope,
see below.
(In spectroscope, no Co-lines, but strong Na-reaction.)
ANALCIME: Na20 14-0, APO* 23-3, SiO2 54-5, H2O 8-2; but a
small percentage of CaO present in some varieties and K2O in others.
Regular ; crystals either small cubes with angles replaced by the planes
of the trapezohedron 2-2, or the latter form alone. Colourless, white,
light-grey, flesh-red ; H 5*5 ; G 2-1-1 -3. Fusible without intumescence
into a more or less clear glass. Decomposed by hydrochloric acid with
separation of slimy silica. See Note at end of Table. Cuboite is a
green or greenish -grey variety. Eudn ophite is regarded as a Rhombic
Analcime. Cluthalite is a somewhat decomposed variety.
NATROLITE (Mesotype in part) : Na*O 16-30, APO3 26-96, SiO*
47-29, H2O 9-45, but traces of CaO, &c., occasionally present.
Rhombic ; crystals very small, often acicular ; essentially Rhombic
(almost rectangular) prisms, terminated by the planes of a rhombic
octahedron. Y: Y 91°; P: P, over polar edges, 143° 20'aiidl42° 40'.
Occurs also, and more commonly, in radio-fibrous masses, often with
crystalline botryoidal surface. Colourless, white, yellow, light-brown,
* If a zeolitic mineral do not shew these spectroscopic reactions very distinctly when simply
moistened by hydrochloric acid, a portion m fine powder should be dissolved in the acid m a
Binall porcelain capsule with attached handle (like that figured on page 20) over the spirit-lamp
or Bunsen-flame. A drop of the solution may then be takeh up by a platinum wire (bent at the
extremity into a small loop or ear) and held within the edge of the flame, care being taken to
test the wire previously for negative results. By this treatment, distinct although more or less
transitory spectra are always obtained when lime, baryta, potash.. &c., are present in the mineral.
266 BLOWPIPE PRACTICE.
red ; two or more tints frequently present in concentric zones in the
same example. H 5-0-5-5 ; A 2-17-2-27. Very easily fusible in the
simple candle or Bunsen-flame, without intumescence, into a colourless
glass. Decomposed, with gelatinization, by hydrochloric acid,
Eadiolite or Bergemanite, Lehuntite, Galactite, Brevicite, Fargite,
are varieties. Mesolite (AntrimoKte, Harringtonite) is a closely
related zeolitic mineral, but contains both lime and soda, and is thus
intermediate between Natrolite and Scolecite. It occurs essentially in
radio-fibrous masses and acicular crystals. Yields 12 to 14 percent,
water ; gelatinizes in hydrochloric acid, and fuses quietly or with very
slight intumescence.
B».-FUSIBLE WITH MUCH BUBBLING OR WITH PREVIOUS INTUMESCENCE.
T Undissolved or scarcely attacked by hydrochloric acid.
(In yellow, fibrous examples. BB, strong Mn-reaction.)
CARPHOLITE : MnO, FeO, Fe2O3, AFO3, SiO2, IPO (10 to 11 per
cent.), with small amounts of MgO, F, &c. Acicular, or in radio-
fibrous aggregates of a straw-yellow or greenish-yellow colour and
silky lustre; H 4-5-5*0; G 2-9-3-0. The water evolved by strong
ignition deposits spots of silica on the sides of the bulb-tube, and
attacks the glass. BB, intumesces and forms a dull-brownish bead.
(In opaque, prismatic crystals. )
GIGANTOLITE : Na2O 1-2, K2O 27, MgO 3-8, MnO 0-9, A12O325-0,
Fe2O3 15-6, SiO2 46-3, H2O, 6-0. Rhombic ; crystals (probably pseudo-
morphous after lolite), thick, twelve-sided prisms, more or less dull ;
green, greenish-grey ; H 3'5 ; G 2'8-2-9. Fusible with bubblingjnto
a greenish slag. When ignited and moistened with hydrochloric acid,
shews red K-line distinctly in spectroscope.
(In pale-red cleavable masses.)
WILSONITE : K2O, CaO, MnO, FeO, A12O3, SiO2, H2O. In rose-red
or pale purplish-red cleavable masses ; slightly tibroi s and pearly in
the cleavage directions, lustreless and more deeply-coloured trans-
versely; cleavage rectangular; H S'0-3'5 on cleavage surfaces, other-
wise 5'0-5'5 ; G 275-2*8. BB, expands or increases in volume, and
fuses with slight bubbling into a very blebby glass or white enamel.
MINERAL TABLES I XXVII. 26Y
Moistened with hydrochloric acid, shews Ca-lines in flashes, and red
K-line persistently.*
f f Decomposed by hydrochloric acid, with separation of granular or
slimy silica.
(Hardness 6'0 or 7'0. Scratch glass strongly.)
PREHNITE: CaO 27-14, APOS 24-87, SiO2 43-63, IPO 4-36.
Rhombic ; crystals tabular or short-prismatic, in aggregated groups
(see Note at end of Table). Occurs also, and more commonly, in
radio-fibrous masses with botryoidal and crystalline surface; greenish-
white passing into distinct shades of green; H 6-0-7'Q; G 2-8-3-0.
Fusible with continued bubbling. In spectroscope, when moistened
with hydrochloric acid, especially after fusion, shews red and green
Ca-lines in flashes. The fused bead gelatinizes in the acid, but in its
normal state Phrenite is more or less slowly and incompletely decom-
posed, with separation of fine granular silica. Konpholite is a thin
tabular variety, which blackens on ignition from the presence of
intermixed dust or organic matter. Chlorastrolite from Isle Royale,
Lake Superior, in small nodular masses of green colour and radio-
fibrous structure, is also a variety or related substance, intermixed
with grains of magnetic iron ore, &c.
FAUJASITE: KX> 4-36, Na2O 4-84, CaO 4-36, APOS 16-00, SiO8
46-77, H2O 28-03. Regular; crystals, small octahedrons (or accord-
ing to Knop, very flat-planed trapezohedrons), sometimes twinned ;
white or brownish ; H 6-0 ; G 1-9-1-95. BB, intumesces, and fuses
readily. In the bulb-tube yields a large amount of water.
(H 4-5 to 5'0. No essential precipitate formed in the diluted solution on addition
of ammonia. )
APOPHYLLITE (Ichthyopthalmite) : CaO 24-72, SiO8 52-97, H2O
15 '90, KF 6-40. Tetragonal ; crystals commonly square prisms with
truncated angles, or acute square-based octahedrons, mostly with
basal plane (see Note at end of Table); colourless, pale-red, brownish,
&c., with pearly lustre on basal plane, the latter also frequently
iridescent; H 4-5-5-0; G 2'3-2'4. BB, exfoliates, and melts with
* Whilst this mineral has much the composition of a Finite, its general aspect ami physical
characters are very different, and have caused it to be regarded as an altered Scapolite. The
presence of potash is the chief object-ion to the latter view. Were it not for its sub-fibrous
structure, as seen on the cleavage surface more especially, it might be considered an altered
Oithoclase.
268 BLOWPIPE PEACTICE.
bubbling to a white glass. Gives fluorine reaction with fused
phosphor-salt in open tube (page 26). Moistened with hydrochloric
acid, shews Ca-lines in flashes, and persistent red K-line. Albin is
an opaque-white, slightly weathered variety. Oxhaverite, Tesselite,
are also varieties.
OKENITE : CaO 26-42, SiO 56-60, H?O 16-98. Rhombic in crystal.,
but chiefly in fibrous masses, more or less tough; colourless, pale-
bluish or yellowish- white ; H 5 -0 ; G 2-28-2-36. Fusible with bubbling
into a white glass or enamel. In spectroscope, no red K-line.
PECTOLITE : See under B2, above.
(H 5*0 to 5'5. A marked precipitate [insol. in acids] formed in the diluted
solution by sulphuric acid.)
BREWSTERITE : BaO, SrO, APO, SiO2, H2O (13-6 per cent.), with
traces of CaO, &c. Clino-Rh.; crystals, small, vertically -striated
prisms, terminated by the two planes of a very flat side-polar or clino-
dome; Y:Y 136°; P on P over summit 172°. Yellowish-white,
pale-brown; H 5'0-5'5 ; G 2-2-2-45. Fusible with intumescence and
bubbling. Moistened with hydrochloric acid, shews in spectroscope
transitory Ba and Sr lines (see page 56), but in some examples the
reaction is not very strongly marked.
(H 4'5 or less. Crystalline and cleavable. A copious precipitate in diluted solu-
tion thrown doivn on addition of ammonia.)
CHABASITE: Average composition: K2O T98, CaO 9-43, A12O»
17-26, SiO2 50-50, H'O 20-83. Hemi- Hexagonal ; crystals, commonly
small rhombohedrons, often twinned, the twin-axis corresponding
with the vertical axis ; R : R 94°-95°, commonly 94° 46' (see Note at
end of Table); colourless, white, pale-red, &c. ; lustre, vitreous; H
4'0-4'5 ; G 2 '0-2 -2. BB intumesces and fuses into a very blebby
glass or white enamel. Decomposed by hydrochloric acid, with
separation of slimy silica. In spectroscope, the solution, or a splinter
moistened with the acid, shews red and green Ca-lines in flashes, with
feeble and very transitory display of the red K-line. Acadialite is a
reddish Chabasite from Nova Scotia. Phacolite is a variety in inter-
penetrating very obtuse twelve-sided pyramids (with other accom-
panying forms), often lenticular from distortion. Haydenite and
Seebachite are also varieties. Levyne and Herschellite are closely
MINERAL TABLES: — xxvn. ?69
related compounds, occurring mostly in hexagonal or pseudo-hexagonal
tabular crystals with large basal plane. Gmelinite is also very
similar, but gelatinizes in hydrochloric acid : see below, page 271.
STILBITE (Desmine of German systems) : CaO 9, APO3 1 6, SiO2 f>?,
IPO 17, with, occasionally, traces of Na2O and K2O. Rhombic;
crystals small and commonly in groups, consisting usually of a
rectangular prism ( = V, Y, the V planes vertically striated), ter-
minated by a rhombic octahedron P, the latter measuring 119° 16'
and 114° over polar edges, and occasionally having its apex truncated
by a small basal plane. Cleavage very perfect parallel to the side
vertical or brachypinakoid V, the cleavage-lustre strongly pearly.
Occurs also abundantly in radio-fibrous and leafy aggregations.
Colourless, white, red, brown, <fec.; H 3-5-4-0; G- 2-1-2-2. BB,
intumesces, and fuses into a very blebby glass. Decomposed by
hydrochloric acid, with deposition of slimy silica. Epistilbite agrees
in composition and general characters, but its crystals are small
rhombic prisms terminated by the front and side polars P and P, the
latter predominating. Y:Y 135° 10'; P:P~over summit 109° 46',
P:P147°40'. Colourless or bluish- white. In hydrochloric acid,
decomposed with separation of fine granular silica.
HEULANDITE (Stilbite of most German systems): CaO (with small
amount of Na2O and K2O) 9-34, APO3 16-83, SiO2 59-06, HX) 14-77.
Clino-R-hombic ; crystals mostly tabular parallel to the side or clino-
vertical plane ; commonly made up of the front and side verticals
Y and Y (the latter predominating) with a front polar P, and narrow
Base. When lying consequently with Y upwards, the crystals
present a pseudo-hexagonal aspect. P: Y 129° 40'; B: Y 116° 20'
and 63° 40'. Cleavage very perfect parallel to A7, the planes, as in
Stilbite, strongly pearly. Colour, hardness, and other characters,
physical and chemical, like those of Stilbite. Euzeolite, Lincolnite,
Beaumontite (?) are varieties.
(In amorphous examples without distinct cleavage. )
CHONIKRITE: CaO, MgO, APO3, SiO2, IPO (9 per cent.). In
snow-white or pale-yellowish, disseminated masses; H 2-5-3, more
or less sectile ; G 2-9. BB, fusible with bubbling into a greyish-
270 BLOWPIPE PRACTICE.
white glass or enamel. Decomposed by hydrochloric acid, with
separation of granular silica. Hitherto, from Elba only. Related
to Pyrosclerite, page 265 above.
Iff Decomposed, with perfect gelatinization, ly hydrochloric acid.
' (BB, sulphur-reaction with carb. soda.)
ITTNERITE : K2O, Na2O, CaO, AW3, SiO2, H20 (9-8 per cent.) In
small, granular masses, with dodecahedral cleavage, of a grey or blue-
grey colour. H 5-0-5-5 : G 2-3-2-4. Fusible with strong bubbling
into a blebby semi-opaque glass or enamel. Yields gypsum to boiling
water, as recognized by the precipitates formed in the solution by
oxalate of ammonia and chloride of barium, respectively (Fischer).
Decomposed by hydrochloric acid, with emission of sulphuretted
hydrogen and separation of gelatinous silica. An altered Hauyne or
Nosean, see page 236.
(BB, flame-border coloured distinctly green.)
DATOLITE: CaO 35-0, B2O3 21-9, SiO2 37'5, H20 5-6. Clino-
Rhombic (or Ortho-Rhombic T) ; occurs commonly in groups of small
vitreous crystals, rich in planes (see Note at end of Table), or in
coarsely granular masses. Greenish-white, colourless, green, reddish-
white. H 5-0-5-5 ; G 2-8-3-0. Fuses very easily, with much bubbling,
and green coloration of the flame, to a colourless or very lightly-
tinted glass. Gelatinizes in hydrochloric acid. In spectroscope,
shews per se two vivid green lines with one pale-green and a faint
blue line, from presence of B203. When moistened with hydrochloric
acid, a test-fragment shews also red and green Ca-lines in flashes ; but
the presence of lime is best shewn by a drop of the solution, taken
up in a double-loop of clean platinum wire and held against the edge
of the Bunsen-flame. Humboldtite is a variety in small crystals,
associated with lamellar Apophyllite, from the Tyrol.
BOTRYOLITE : Contains 10*64 per cent, water, and occurs in fibro-
botryoidal examples of a greenish, pale-grey, or reddish colour;
otherwise like Datolite.
(Moistened with hydrochloric acid, shew distinct red K-line in spectroscope.)
PHiLLiPSiTE(Lime-Harmotome, Christianite) : Average composition,
K20 7, CaO 6, A12O3 21-5, SiO2 48-5, H2O 17. Rhombic (?); com-
monly in cruciform crystals resembling those of Harmotome (see
MINERAL TABLES : XXVII. 271
Note at end of Table). Colourless, white, reddish-white, pale-grey,
&c.; H 4-5-5-0 ; G 2-15-2-2. Fusible with intumescence and bubbling.
Gelatinizes in hydrochloric acid. The moistened test, or the solution,
shews K and Ca-lines in spectroscope, the latter in flashes only.
GISMONDINE : K20 2-85, CaO 13-12, AFO 27-33, SiO2 35-88, H2O
21-10. Tetragonal (or Rhombic?); crystals small, and often imper-
fectly formed or sub-spherical, consisting commonly of a simple pyramid
or octahedron (with angle of 118° 30' over polar edge, and 92° J$0'
over middle edge), or of this form combined with the prism V;
greyish or reddish- white ; H 5*0-6-0; G 2-27. Fusible with intu-
mescence. See Zeagonite, below.
ZEAGONITE: K20 11-09, CaO 5-31, APO3 23*34, SiO2 43-95, H20
15*31. Rhombic; crystals mostly, rectangular prisms (composed of
V and V) with angles replaced by a rhombic octahedron P, measuring
121° 44' and 120° 37' over polar edges, and 89° 13' over middle
edges, the planes often rounded and the crystals in sub-spherical groups.
Colourless, white, pale-bluish ; H 5*0-6-5 or 7, the latter at the points
and edges. Fusible with intumescence. Probably identical with
Gismondine, both being Rhombic, with pseudo-tetragonal aspect. In
spectroscope, the red K-line comes out very distinctly.
GMELINITE ; THOMSONITE : Shew sometimes in spectroscope a feeble
or indistinct K-line : see below.
HYDROTACHYLITE : In -vitreous, amorphous masses : see below,
page 273.
(No distinct K-line brought out in spectroscope).
GMELINITE : Average composition — Na20 (with small amount of
K20) 5, CaO 5; A12O3 20, SiO2 48, H20 21. Hexagonal or Hemi-
Hex. ; crystals, commonly, very short six-sided prisms (horizontally
striated), combined with a six-sided pyramid measuring 142° 33' over
polar edges, and 79° 54' over middle edges; but the planes of the
latter often alternate in size, and hence the pyramid is regarded as
consisting of two complementary rhombohedrons, with R : R = 1 1 2°
26'. Colourless, greenish-white, yellowish-white, pale-red. H 4*5 ;
G 2*0-2*1. Fusible with intumescence. Is closely allied to Chaba-
site, but is distinguished by the presence of Na2O, and by its perfect
gelatinization in hydrochloric acid. Ledererite is a variety.
THOMSONITE (Comptonite) : Ka2O (with small amount of K2O, 4*4,
CaO 13-3, A1203 30*6, SiO2 38*7', IPO 43. Rhombic in crystallize.
272 . BLOWPIPE PRACTICE.
tion, but cr}Tstals usually small or acicular (see note at end of Table),
essentially eight-sided prisms composed of the forms V, Y, and V,
with V planes vertically striated (V:V 90C 40'). Occurs chiefly in
fibrous and fibre-spherical masses. Colourless, white, reddish-white,
brown. H 5'0-5'5 ; G 2-35-24. Fusible with intumescence. Gela-
tinizes in hydrochloric acid. In spectroscope the solution or mois-
tened fragment shews red and green Ca-lines. Ozarkite, according to
Dana, is a massive Thomsonite. Faroelite, Scoulerite, Chalilite, are
also varieties ; the latter red-brown, and partially altered.
SCOLECITE (Mesotype in part): CaO 14-26, APO3 26-13, SiO'
45*85, H20 13-76. Clino-Rhombic ; crystals mostly rhombic prisms
(with Y : V 91° 35') with low pyramidal terminations (P and - P'),
hence much resembling an ortho-rhombic combination. In. general,
however, crysts. very small or acicular. Occurs commonly in fibrous
and radio-spherical examples. Colourless, white, reddish-white, <fec. H
5-0-5-5 ; G 2-2-2-4. Fusible with intumescence, the more typical
examples curling up greatly. Acid and spectroscope reactions like
those of Thomsonite. Poonahlite is a variety. Mesolite is also closely
related, but contains both soda and lime, and fuses more or less
quietly. See under Natrolite, page 266.
LAMONTITE: CaO 12, APO3 22, SiO? 50, H20 16; but the latter
usually less, from the ready efflorescence of the mineral. Clino-
Rhombic ; crystals essentially rhombic prisms, with Y : Y (in front)
= 86° 16', terminated by a very oblique front-polar or hemi-ortho-
dome* inclined on the Y planes at angle of 1 1 3° 30'. Cleavage very
perfect parallel to Y. Occurs also very commonly in columnar,
fibrous, and sub-earthy masses. White, yellowish or reddish-white,
pale-red, pale- grey. H 3-5-4-0 normally, but often less from partial
disintegration. G 2-25-2'36. Fusible with intumescence into a white
enamel or very blebby glass. Gelatinizes in hydrochloric acid. A
drop of the solution on loop of platinum wire, or a moistened frag-
ment of the mineral, shews in spectroscope red and green Ca-lines.
Leonhardite, Caporcianite, and ^Edelforsite,t are identical or closely
related.
* The Basal plane of French crystallographers.
t This is the so-called " Red Zeolite of ^Edelfors." Its hardness is usually stated in text-
books to equal 6'0, an error arising from a confusion of names —the degree of hardness in ques-
tion applying to an older "^Edelforsite," since shewn to be an impure Wollastonite containing
intermixed quartz.
MINERAL TABLES :— XXVII. 273
(In vitreous, amorphous masses).
HYDROTACHYLITE : K2O, Na20, CaO, MgO, FeO, Fe203, APOS,
TiO2, SiO2, H2O (12-90 per cent.), according to Peterson and Senfter.
Forms nodular and other masses of uncrystalline structure in basalt.
Dark-green or black. H 3'5; G 2'13. Fusible with more or less
bubbling. Decomposed, with gelatinization, by hydrochloric acid.
See Tachylite, page 228.
NOTE ON TABLE XXVII.
Many of the minerals placed (to avoid risk of error in their determination)
in the present Table, belong properly — on account of their difficult fusibility
or slight percentage of water— to preceding Tables, and are described more
fully in these latter. The various Micas, Talc and Steatite, Agalmatolite, the
Pinites, &c. , are examples. See more especially the Note to TABLE XXV.
The minerals which belong essentially to the present Table consist for the
greater part of zeolites — hydrated silicates of very characteristic occurrence in
trappeari or basaltic rocks. With these, in a Determinative grouping, the
boro-silicate Datolite may be conveniently placed, as it resembles many
zeolites in general characters, and is also frequently present in amygdaloidal
traps. The zeolites, as the name implies, either swell up or intumesce on the
first application of the blowpipe-flame, or otherwise melt very easily, and
generally with bubbling. All, when reduced to powder, are readily decom-
posed by boiling hydrochloric acid, the silica separating in many cases in a
gelatinous form. The presence of CaO, BaO, or K20. is easily ascertained by
the pocket-spectroscope, if a drop of the solution be taken up in a small loop
of platinum wire and held within the edge of a Bunsen-flame. As a rule,
when lime and potash are present together, the red and green Ca-lines come
out first, and then, as these fade away, the red K-line comes into view.
In the present Note, only the more common of these minerals are referred
to, the crystallographic and other characters of the less important species
being given in sufficient detail in the Table. The commonly occurring species,
as regards their blowpipe reactions, fall into three series, as follows :
§ 1. Fusible quietly : (a) soda-species : Analcime, Natrolite ; (b) barytic
species : Harmotome.
§ 2. Fusible with much bubbling, but without (or without marked) intu-
mescence* on first application of the flame : Datolite ; Prehnite.
§ 3. Curling up or intumescing on first application of the flame : (a) lime-
potash species : Apophyllite, Phillipsite ; (b) gelatinizing lime-species : Thom-
*By "intumescence" is meant, here, not a mere expansion of the substance, but a throwing
out of excrescences or curling up after the manner of borax. Minerals which intumesce in
this manner on the first application of the flame, fuse afterwards in general without bubbling,
and, as a rule, somewhat slowly.
19
274 BLOWPIPE PRACTICE:.
sonite, Scolecite, Laumontite ; (c) non- gelatinizing lime-species: Chabasife,
Stilbite, Heulandite.
The leading characters of these species are given in the Table, but neces-
sarily in brief form only ; a few additional references to their crystallization
are therefore appended.
Analcime, in most examples, is at once recognized by its crystals, as these
are generally well-formed and easily made out. They belong to the Regular
System, and consist either of the trapezohedron 2-2 (measuring 131° 48' 36"
over long or axial edges, and 146° 26' 33" over intermediate edges), or of a
combination of this form with the cube, the latter commonly predominating
and thus having each angle replaced by three triangular planes (with inclin-
ation of cube-face on abutting 2-2 face measuring 144° 44').' The cleavage is
cubical, but very indistinct. In the spectroscope, as a rule, no other line than
a strong Na-line is observable if the test-matter be carefully freed from
accompanying calcite.
Crystallized Natrolite was formerly and is still often known as Mesotype,
the term Natrolite having been originally limited to the yellowish-brown,
concentric-fibrous variety, then regarded as distinct. The crystals belong to
the Rhombic System, but are frequently acicular, or are only partially formed
(as polar planes) at the extremities of the fibres of which ordinary .examples
are so commonly composed. When distinctly formed, they consist of a nearly
rectangular prism with front angle ( — V : V) of about 91°, terminated by the
planes of a somewhat low pyramid or octahedron measuring 143° 20' and
142° 40' over polar edges, and 53° 20' over middle edge. P on V, conse-
quently, measures 116° 40'. The prism-planes in most examples are striated
vertically (sometimes very coarsely), and occasionally either the front or side
edges are replaced by V or V. In the spectroscope, pure examples as a rule
shew only a strong Na-line, but transitory flashes of red and green Ca-lines
sometimes appear.
Harmotome, a barytic zeolite, is in general readily recognized by its small,
symmetrically formed cruciform crystals, although, occasionally, re-entering
angles in these are more or less inconspicuous or are indicated only by striae.
The crystallization is apparently ' Rhombic, but the crystals have to some
extent a Tetragonal aspect. They consist commonly of a rectangular prism
(composed of the forms V and V), terminated by the planes of an octahedron
or pyramid, P, or occasionally by those of a side-polar or brachydoir e P. In
some crystals, the polar planes are simply striated ; in others, the V planes
shew a lozenge-shaped striation.* Two (or four) of these crystals form inter-
penetrating twins, with vertical axis in common. P : P, over polar edges,
120° 1' and 120° 42' ; P : P 110° 20'. Cleavage, V distinct, V somewhat less
apparent. A drop of the hydrochloric acid solution, taken up in a loop of
* Some crystallographers (after Des Cloizermx) make the System Clino-Rhombic, and regard
this front-vertical form as the basal form. On that view, most of the crystals will be elongated
in the direction of the clino-axi».
MINERAL TABLES : — XXVII. 275
platinum wire, shews the green Ba-lines in the spectroscope very distinctly.
The diluted solution gives also a marked precipitate with a drop of sulphuric
acid.
Datolite — a hydrated boro-silicate of lime— is described fully, as regards its
more distinctive characters, apart from crystallization, in the Table. Its
crystals belong to the Clino -Rhombic system, but many (the Arendal crystals
especially) are strikingly Ortho-Rhombic in aspect. These latter are chiefly
in the form of rhombic or six-sided tabular crystals, composed of the forms V
and V, with broadly-extended basal plane, and commonly with a front-polar
or orthodome ( - 2P) and other polar planes subordinately developed. In
many crystals these polar planes appear equally at corresponding extremities,
with but little if any difference in their angle values, and thus impart an
Ortho-Rhombic character to the crystal. In crystals from other localities,
however, and in some of the Arendal crystals, they are developed only at one
extremity. In the Andreasberg and most other crystals, the basal plane is
also well-developed as a rule, but the prism-planes (V, V£, and V) and certain
polar planes (especially - 2P, - P, and the side-polars or brachydomes 2 P
and 4P) are also well formed, and the crystals are thus more short-prismatic
than tabular. In some crystals, again, the basal form is entirely absent.
The principal^ angles are as follows : V : V 76° 38' ; V£ : V£ 115° 22' ; V : Vfc
160° 38' ; B : V 90° 6' (and 89° 54') ; B : - 2P 135° 4'. The marked green color-
ation (from the presence of B203) which datolite imparts to the flame of the
blowpipe or Bunsen burner serves at once to distinguish it from other minerals
of similar aspect.
Prehnite is distinguished from other Zeolites by its high degree of hardness?
( = 6 to 7), and its small percentage of water. It occurs most commonly in
botryoidal masses with crystalline surface and radio-fibrous structure, the
colour varying from pale greenish-white to deep apple-green. Distinct crys-
tals are comparatively rare. They belong to the Rhombic System, and pre-
sent four types : (1), The symmetrically tabular type — in which the crystals
arc thin rhombic tables composed of the forms V and B ; or six-sided tables
composed of V V and B ; or eight-sided tables made up of V, V, V, and B,
the basal form in each case greatly preponderating. (2), The tabular type
with brachydiagonal elongation — in which the thin crystals contain the forms
V, V and B, and are greatly extended along the two latter, thus passing at
times into fibrous aggregations with the two front planes of V at the free end
of the fibres. (3), The short-prismatic type with development of side or
brachy-forms — the crystals of this type being composed essentially of the
forms V and B, with V and 3P at the sides, the planes of the rhombic prism
V preponderating ; and (4), The short-prismatic type, with front or macro-
forms — the crystals presenting the forms V and B, as preponderating forms,
with the front- vertical V, and the front- polar or rnacrodome |P subordinately
developed, in addition occasionally to the planes of the rhombic pyramid P,,
276 BLOWPIPE PRACTICE.
forming a narrow border to the basal plane. V : V 99° 56' ; B : 3P 106° 3$ ;
B : fP 134° 52'. The vertical faces are frequently convex, whilst the basal
plane is more or less concave, and from the aggregation of these curved crys-
tals, parallel to B, globular or spheroidal examples commonly arise. For
other characteristics, see the Table.
Apophyllite is distinguished chemically by its fluorine reaction, by the
absence of alumina, and by the persistent K-line which it exhibits in the spec-
troscope when moistened with hydrochloric acid. Its Tetragonal crystals are
in general distinctly formed, and are thus easily recognized. They present
three more or less distinct types : (1), A prismatic type — in which the crystals
are simple square prisms (V, B), with angles replaced by the triaxial pyramid
P ; (2), A tabular type — in which the crystals present a large base, with V
and P depressed to little more than a narrow border around it ; and (3), A
pyramidal type — in which the pyramid P essentially^predominates, although
combined with the front- vertical form or pinakoid, V, and occasionally with
the octagonal prism V2 (which appears as a bevelment on the vertical edges of
V). The basal plane, with its peculiar iridescent-pearly lustre, is also fre-
quently present in this type, but it is always of small size, and the general
aspect of the crystals is essentially pyramidal. P : P over polar edge 104° to
104° 20', over middle edge 120° to 121°. B : P about 119° 30'. The cleavage
is basal and very perfect, the points of the pyramid consequently are com-
monly broken off. Twin crystals, so commou in many Zeolites, are in this
species all but unknown.
Phillipsite is also a potassic species, but differs from Apophyllite by con-
taining alumina, as well as by the absence of fluorine, and essentially by its
crystallization. It differs also by its complete gelatinization in hydrochloric
acid. Its crystals are practically identical with those of Harmotome (see
above), and thus consist essentially of a rectangular prism (V, V) terminated
id
by the polar forms P, P ; two (or four) crystals being united in cruciform
twins. In some crystals, the vertical planes look like those of a simple prism,
but the compound nature of the crystal is revealed by the re-entering angles
at the summit. In general, however, the cruciform character of the crystals
\j %j
is sufficiently distinct. The planes of the forms P, P, and V, are transversely
striated.
Thomsonite occurs chiefly in fibrous and acicular forms, but is also found in
small, distinct crystals. These belong to the Rhombic System, and present
two types or varieties : (1), The Thomsonite type, proper, in which the crys-
tals are short, large-based, vertically-striated rhombic prisms, V, replaced on
the acute edges by the side or brachy-vertical V, and on the obtuse edges and
angles by the front- vertical V, and front-polar or macrodome mP ; and (2),
The Oomptomite type, in which the crystals form short eight-sided prisms
(composed of the forms V, V, V) with the two planes of an exceedingly flat
brachydome or side-polar l/mP entirely occupying the position of the base. The
MINERAL TABLES : XXVII. 277
prism V is nearly square, its front-angle measuring 90° 40'. The flat brachy-
dome planes meet (according to Des Cloiseaux) at an angle of 177° 23'.
Crystals of Scolecite very closely resemble those of Natrolite or Mesotype,
as they consist of nearly square prisms terminated at each extremity by four
pyramidal planes. But whilst Natrolite crystals are clearly Ortho-Rhombic,
Scolecite crystals are regarded as Clino-Rhombic, the pyramidal planes at the
top and bottom of the crystal, respectively, differing slightly in their inter-
facial angles. These angles, nevertheless, closely correspond to those of
Natrolite. V : V = 91° 35' (in Natrolite 91°) ; P : P, over polar edge in front,
144° 20' (in Natrolite 143° 20') ; -P : -P 144° 40'. Occasionally the prism is six-
sided, its acute edges being replaced by "the side-vertical V, Scolecite differs,
however, essentially from Natrolite in being a lime-species in place of a soda-
species, and by its remarkable blowpipe comportment : as, whilst Natrolite
fuses quietly, Scolecite expands and curls up or throws out excrescences on the
first application of the flame, at least in all typical examples. Some examples
are said to fuse without intumescence, but these are probably soda-holding
varieties, or Mesolite. All essentially calcareous zeolites exfoliate or intumesce
before the blowpipe, or otherwise fuse with continued bubbling. Purely
alcaline zeolites, on the other hand fuse quietly.
Laumontite when in crystals is easily recognized, but when in fibrous masses
it is distinguished with difficulty from other calcareous zeolites. A somewhat
salient character is its great tendency to fall into a white, earthy powder from
efflorescence. The crystals are Clino-Rhombic, and they consist most commonly
of a simple rhombic prism terminated obliquely by a single plane. The latter
is the basal plane of most French crystallographers, but is commonly made
the plane of a hemi-orthodome or front-polar -P. The prism-angle V : V, in
front, equals 86° 16' ; V : -P = 1 13° 30'. Very frequently the opposite angle of
the prism is replaced by the corresponding hemi-orthodome P, the latter
inclining to a face of the prism at an angle of 104° 20'. Often, also, other
polar planes (P, &c.) are subordinately present, and the vertical edges of the
prism are sometimes- slightly truncated by V and V. Spectroscopic and other
characters are given in the Table.
Chabasite is easily distinguished from other zeolites by its rhombohedral
crystallization. The crystals, although small, are in general distinctly formed,.
They consist essentially of cuboidal rhombohedrons, with R : R measuring
over polar edges 94° to 95°, usually 94° 46', whence the old French name of
zeolite cubiqne by which the species was at one time known. In many
examples, this rhombohedron occurs in the simple state, but very often its
polar edges are replaced by an obtuse rhombohedron - ^R^and its middle angles
by the acute form - 2R, measuring respectively over their own polar edges,
125° 13', and 72° 53'. R on - £R = 136° 23' ; R on - 2R = 1 19° 42'. The planes
of the chief rhombohedron, R, are sometimes striated parallel to the polar
edges, the stride meeting in the line of the longer diagonal of each plane. These
striae indicate a very obtuse scalenohedron, occasionally present in Chabasite
crystals. An obtuse twelve-sided pyramid §P2 (with angle of 145° over polar
278 BLOWPIPE PRACTICE.
edges) is the predominating form in the Bohemian variety known as Phacolite.
This variety occurs in interpenetrating twins ; and twin-forms, with the
vertical axis in common, are of frequent occurrence in crystals of Chabasite
generally. The solution in hydrochloric acid, in which the silica separates in
a slimy or at times in almost a gelatinous condition, shews in the spectroscope
a vivid calcium spectrum, and as this fades out a transitory red K-line generally
comes into view.
Stilbite and Heulandite may in general be distinguished easily from other
zeolites by their almost constant occurrence in bladed or narrow -foliated
examples, with very perfect cleavage in one direction and strong pearly lustre
i >
on the cleavage surface. The latter is parallel to a side- vertical, V, or (in
Heulandite) V. The hardness, also, is lower than in most other zeolites, viz.c
3'5-4'0. The free ends of the foliae generally shew crystalline facets. The
colour is commonly either white, red, or light-brown. In Stilbite, the crystal-
system is Rhombic, and the more common crystals consist of a rectangular
prism (V, V, usually flattened parallel to V, the cleavage plane), with the
planes of a rhombic octahedron, P, at each extremity. Occasionally, the
vertical edges of the rectangular prism are slightly replaced by the rhombic
prism V, and the point of the octahedron is truncated by the basal form B.
The prism-angle, V : V, equals 94° 16' ; P : P over front polar edge, 119° 16' ;.
over side polar edge, 114° ; over middle edge, 96°.
In Heulandite, the system is Clino-Rhombic. The more commonly-occurring
crystals .are made up of the front-vertical form V, the side or clino- vertical V,
the front-polar or hemi-orthodome P, and the basal form B. The side- vertical
V (the cleavage plane) generally predominates, the crystals being usually
much flattened in that direction ; but occasionally,, crystals are elongated
transversely, i.e,, in the direction of the ortho-diagonal or right-and-left axis,
in which case the frontal forms V and P preponderate. The hemi-pyramids
2P and §P, and the clinodome or side-polar 2P, also occasionally occur as sub-
ordinate forms. P:V equals 129° 40' ; B : V, 116° 20'; 2P:2P, in front,.
J36° 4' ; §P : |P, 146° 52' ; 2P : 2P, over summit, 98° 44'.
Although both Stilbite and Heulandite are essentially lime species, they
usually contain small amounts of soda and potash. When a drop of the-,
hydrochloric-acid solution (taken up in a loop of clean platinum wire) i&
examined by the spectroscope, the red K-line, therefore, almost always
appears for an. instant, a,s the vivid re.d an,d. green Ca-Uues fade out of
INDEX
TO THE MINERALS IN PART II.
Abichite, 144.
Abrazite (v. Gismondine).
Acadialite, 268.
Acanthite, 107,
Acanticone (v. Epidete),
Acmite, 232.
Actinolite, 233.
Adamvantine Spar, 196, 207.
Adamite, 145.
Adularia Feldspar, 245, 253.
^Edelforsite, 272.
.^Egirine, 233.
^schynite, 126.
Agalmatolite, 219.
Agaric Mineral (v. Calcifce).
Agate, 20&
Aikinite, 107.
Alabandine, 108, 124, 152.
Alalite, 243.
Albertite, 132,
Albin, 268.
Albite, 246, 254.
Alexandrite (v. Chrysoberyl)-
Algodonite, 10L
Alipite, 217.
Alisonite, 107.
Allauite, 228.
Allemontite, 101.
Allochroite, 228,
Alloclase, 103.
Allophane, 217.
Almandine, 230,
Alstonite, 137.
Altaite, 113.
Alum, 154.
Alumstone, 155.
Aluminite, 155, 162.
Alunite, 155.
Alunogene, 154,
Amalgam, 115.
Amazon-stone, 246,
Amber, 132, 133.
Amblygonite, 164.
Amethyst, 202, 208.
Amianthus, 243.
Ammonia- alum, 154.
Amphibole, 233, 243, 251.
Amphigene (Lencite), 203.
Analcime, 265, 274.
Amatase, 127, 129, 196, 206.
Anauxite, 219.
Andalusite, 199, 210.
Andesiue, 253.
Andradite, 230.
Anglarite (v. Viviamte),
Anglesite, 151, 160.
Anhydrite, 152, 16L
Ankerite, 136.
Annabergite, 145.
Anorthite, 241.
AnthophyUite, 216.
Anthosiderile, 257,
Anthracite, 128, 223.
Anthraconirbe (v. Calcite),
Antigorite, 215.
Antimony, 113.
Antimony Blende, 149.
Antimony Glance, 110, 112.
Antimonial Silver (v. Dyscra-
Antimonial Nickel Glance, 110,
Antimonial Nickel Ore, 114.
Antimony Ochre, 149L
Antimonite, 149.
Antrimolite, 266,
Apatelite, 158.
Apatite, 1£3. 169,
Aphancse, 144.
Aphrodite (Meerschaum?)
Aphrosiderite, 257.
Aphthalose, 153,
Apthonite (Tetrahedrite ?)
Apjohnite, 158,
Aplome, 230.
Apophyllite, 267, 276.
Aquamarine (Beryl), 200,
Arseoxene, 144.
Aragonite, 138, 141.
Arcanite, 153.
Arfvedsonite, 234.
Argentite, 107, 109.
Arkansite, 127.
Arksutite, 178.
Arquerite, 115.
280
INDEX.
Arragonite, 138, 141.
Arsenic, 101.
Arsenical Iron, 101.
Arsenical Pyrites, 103, 104.
Arsenious Acid, ) , ,„
Arsenolite,
Arseniosiderite, 146.
Asbestus, 243.
Asbolan, 189.
Asmanite, 201,
Asparagus stone v. Apatite).
Aspasiolite, 220.
Asperolite, 217.
Asphalt, 132.
Aspidolite (Magnesia Mica).
Astrakanite, 154.
Astrophyllite, 227.
Atacamite, 176, 177.
Atelesite, 145.
Atelite, 176.
Atheriastite.
Atlasite, 176.
Auerbachite, 198.
Augelite, 168.
Augite, 232.
Aurichalcite, 136.
Auripigment (v. Orpinieiit).
Automolite, 197.
Autunite, 166.
Avanturine ( = Quartz with in-
spersed scales of mica,
iron-glance, &c.).
Axinite, 230, 248.
Azurite, 135, 142.
Babingtonite, 233.
Bagrationite, 228.
Baikalite (Amphibole).
Baltimorite, 221.
Bamlite (var. Sillimanite), 200.
Barnhardtite, 105.
Barrandite (Strengite ?), 165.
Barytine, 152, 160.
Barium Mica, 261.
Baryto-calcite, 137, 153.
Baryto-celestine, 152.
Bastite, 215.
Batrachite, 204.
Baudisserite, 139.
Beaumontite, 269.
Bechilite, 172.
Beraunite, 165.
Bergemannite, 266.
Berlinite, 168.
Berthierite, 110.
Beryl, 200, 209.
Berzelite, 146.
Berzeline, 106, 236.
Beudantite, 144,
Beyrichite, 105.
Bieberite, 157.
Bindheimite, 150.
Binnite, lt)3, 104.
Biotite, 213.
Bismuth, 115.
Bismuthine, j 10- lf)Q
Bismuth Glance, ( 1U/> luy'
Bismuth Ochre, 188.
Bismutite, 136.
Bitter Salt (Epsomite), 154.
Bitter Spar, 138.
Bitumen, 132.
Bituminous Coal, 132, 134.
Black Band, 141.
Black Oxide of Copper, 116.
Black Jack, 109.
Blende, 108, 109, 151, 159.
Bloedite, 154.
Bloodstone (v. Quartz).
Blue carb. copper, 135.
Blue Vitriol, 156.
Bodenite, 228.
Bog Iron Ore, 193.
Bog Manganese Ore (Wad), 188.
Bolognese Spar (Barytine), 152.
Boltonite, 204.
Bombiccite, 133.
Bonsdorffite, 220.
Boracite, 171, 173.
Borax, 171, 173.
Bornite, 105, 108.
Borocalcite, 172.
Boronatrocalcite, 172.
Boracic Acid, 171.
Botryogene, 157.
Botryolite, 270.
Boulangerite, 111.
Bournonite, 111, 112.
Bowenite, 221.
Bragite, 127.
Brandisite, 216.
Braumte, 125.
Breislakite, 232.
Breithauptite, 114.
Breunnerite (Mesitine), 136.
Brevicite, 266.
Brewsterite, 268.
Brittle Silver Ore, 110.
Brochantite, 158.
Bromargyrite, 175.
Bromlite, 137.
Brongniardite, 111.
Brongniartine (v. Glauberite).
Bronzite, 216.
Brookite, 127, 199.
Brown Coal, 132.
INDEX.
281
Brown Iron Ore, 125, 128, 187,
192.
Brucite, 190, 194.
Brushite, 168.
Bucholzite, 200.
Bucklandite, 231.
Bunsenite, 190.
Buratite, 136.
Buntkupfererz, 105.
Bustamite, 233.
Byssolite, 227.
Bytownite (var. Anorthite).
Cabrerite, 145.
Cacholong (var. Opal).
Cacoxene, 165.
Cairngorm, 208.
Calaite, 167, 170.
Calamine, 205, 219.
Calamite (Tremolite), 243.
Oalaverite, 113.
Calcedony, 208.
Calcite,
137, 140.
Calc Spar,
Caledonite, 135, 151.
Calomel, 176.
Canaanite (var. Pyroxene).
Caiicrinite, 239.
Cantonite (Covelline ?).
Caporeianite, 272.
Carbonado, 196.
Carminite, 144.
Carnallite, 174.
Carnelian, 208.
Carpholite, 266.
Cassiterite, 127, 195, 206.
Castor, 235.
Cat's-Eye, 208.
Celestine, 152, 160.
Cerargyrite, 175, 177.
Cerine, 228.
Cerite, 205, 218.
Cerussite, 135, 142.
Cervantite, 149.
Ceylanite, 197.
Chabasite, 268, 277.
Chalcanthite, 156.
Chalcedony, 208.
Chalkosine, 106.
Chalilite, 265.
Chalcanthite, 156.
Chalcophanite, 126.
Chalcophyllite, 144.
Chalcopyrite, 105, 108.
Chalcolite, 166.
Chalcotrichite (— Acicular Cu-
prite).
Chalcosiderite, 166.
Chalcosine, ) irw» 1no
Chalkosine, | 106' 109'
Chalcostibite, 111.
Chalibite, 265.
Chalybite (Siderite), 136.
Chatamite, 101.
Chamosite, 256.
Chessylite, 135.
Chesterlite (Orthoclase).
Chiastolite, 199, 223.
Childrenite, 165.
Chile Saltpetre, 181.
Chiolite, 178.
Chladnite (Meteoric Enstatite).
Chloanthite, 101.
Chlor- Apatite, 163.
Chlorastrolite, 267.
Chlorides (v. TABLE XIX. ).
Chlorite, 314, 224, 257.
Chloritoid, 259.
Chloroealcite, 174.
Chloromelane (Cronstedite),
256.
Chloropal, 218.
Chlorophceite, 260,
Chlorophane Fluor Spar).
Chlorophyllite, 215.
Chlorotile, 144.
Choudro-arsenite, 146.
Ckondrodite, 204, 211.
Chonikrite, 269.
Christbphite, 151.
Chromic Iron Ore,, 118, 124, 128.
Chromite, 118, 124, 128, 186,
192.
Chrome Garnet, 198.
Chrome Mica, 213.
Chrysoberyl, 197, 207.
Chrysocolla, 217.
Chrysolite, 204, 210.
Chrysoprase, 208.
Chrysotile, 221.
Churchite, 168.
Cimolite, 219.
Cinnabar, 121, 122, 130, 131.
Cinnamon -stone (Garnet).
Clarite, 103.
Claudetite, 148.
Clausthalite, 106.
Clay Ironstone, 136, 141.
Cleavelandite, 246.
Clinoclase, 144, 147.
Clinochlore, 214.
Clino-Humite, 204.
Clintonite, 216.
Clathalite, 265.
Coals, 132, 134.
Cobalt Bloom, 145.
282
INUEX.
Cobalt Spar, 137.
Cobalt Vitriol, 157.
Cobaltine, 103, 104.
Coccinite, 176.
Coccolite, 232.
Collyrite, 220.
Colophonite, 245.
Colunibite, 126.
Comptonite, 271, 276.
Cookeite, 261.
Copiapite, 158.
Copper, 116.
Copper Binnite, 103.
Copper Glance, 106, 109.
Copper Mica, 144.
Copper Nickel (Nickeline), 101,
102.
Copper Pyrites, 105, 108.
Copper Uraiiite, 106, 170.
Copper Vitriol, 156.
Copperas (Green Vitriol), 156.
Coquimbite, 157.
Coracite, 190.
Cordierite, 200, 211.
Corneous Lead Ore, 176.
Cornwallite (a copper arseniate).
Corundum, 196, 297.
Corynite, 103.
Cosalite, J07.
Cotunnite, 176.
Couserauite, 241.
Covelline, 130.
Crednerite, 126.
Crichtonite (Ilmenite), 118.
Crocidolite, 259.
Crocoisite, 182, 184.
Cronstedite, 256.
Crookesite, 106.
Cryolite, 178.
Cryophyllite, 235.
Cryptolite, 164.
Cryptomorphite, 172.
Cubanite, 105.
Cube Ore, 145.
Cuboite, 265.
Culsageeite, 362.
Curnniingtonite, 234.
Cuprite, 116, 122, 123, 189,
193.
Cuproplurabite, 107.
Cyanite, 197, 210.
Cymophane, 197.
Cyprine, 245.
Damourite, 260.
Pauaite, 103.
Danalite, 229.
Danburite, 236.
Dark Red Silver Ore, 110, 112,
121.
Datolite, 270, 275.
Daubreite, 176.
Davyne, 239.
Davidsonite (Beryl).
Dawsonite, 139.
Dechenite, 182.
Delessite, 214, 257.
Delvauxite (a linie-iron phos-
phate).
Demidowite, 217.
Descloizite, 182.
Desinine, 269.
Deweylite, 221,
Diadochite, 159.
Diallage, 242.
Diallogite, 137.
Diamagnetite, 124.
Diamond, 196, 206.
Diam'te, 196.
Diaphorite, 111.
Diaspore, 196.
Dichroite, 200, 211.
Dihydrite, 167.
Diopside, 243.
Dioptase, 205, 216.
Diphauite, 215.
Dipyre, 241.
Disterrite (Brandisite), 216.
Disthene, 197, 210.
Dolomite, 138, 140.
Domeykite, 101.
Donacargyrite, 111.
Dopplerite, 132.
Dufrenite (Green Iron Ore, an
iron phosphate).
Dufrenoysite, 103, 104.
Durangite, 147.
Dyscrasite, 113.
Dysluite (Gahnite), 197.
Edingtonite, 264.
Egerane, 244.
Ehlite, 166.
Ekebergite (Warnerite), 240.
Elseolite, 239.
Elastic Bitumen, 132.
Elaterite, 232.
Electrum (Amalgam), 115.
Eliasite, 190.
Embolite, 175.
Emerald, 200, 209.
Emerald-Nickel (Zaratite), 139.
Emery, 196, 207.
Emery lite, 215.
Emplectite, 107.
Enargite, 103.
INDEX.
283
Enstatite, 201.
Epichlorite, 214.
Epidote, 231, 249.
Epigenite, 103.
Epistilbite, 269.
Epsomite, 154.
Erdmaimite, 228.
Eremite, 765.
Erinite, 144.
Erubescite (Bornite), 10.5.
Erythrine, 145.
Esmarkite, 220.
Essonite (Garnet),
Ettringite, 156.
Euchroite, 144.
Euclase, 200.
Eucolite, 237.
Eudialyte, 237.
Eudnophite, 265.
Eukairite, 106.
Eulytine, 237.
Euphyllite, 215.
Eupychroite, 163.
Eusynchite, 182.
Euxenite, 127.
Euzeolite, 269.
Evaiisite, 167.
Fahlerz, 110.
Fahlunite, 220.
Fargite, 266.
Farcolite, 272.
Fassaite, 232.
Faujasite, 267.
Fauserite, 158.
Fayalite, 227.
Feather Alum, 157.
Feldspar (lime), 241.
Feldspar (potash), 245.
Feldspar (soda), 245.
Feldspar Group, 253.
Felsobanyite, 155.
Fergusonite, 127.
Fibro-Ferrtfe, 158.
Fibrolite, 200.
Fichtelite, 133.
Figure Stone, 219.
Fire Blende, 149.
Fire Opal, 202.
Fischerite, 167.
Flint, 208.
Flos Ferri, 138.
Fluellite, 178.
Fluocerite, 179.
Fluor-Apatite, 163, 169.
Fluorite, 178.
Fluor Spar, 178, 179.
Foresite (near Stilbite), 269.
Forsterite, 204.
Fowlerite, 233.
Francolite, 163.
Franklinite, 118, 124, 128, 186,
192.
Freislebeiiite, 111.
Frenzelite (Guanajuatite), 106.
Frugardite, 245.
Fuchsite, 213.
Gadolinite, 204.
Gahiiite, 197, 208.
Galactite, 266.
Galena, 107, 109.
Galmei (Calamine), 205.
Garnet, 230, 141.
Garnet Group, 248.
Gaylussite, 138.
Gehlenite, 204.
Geierite, 103.
Genthite, 217.
Geocerite, 133.
Geocronite, 112.
Gersdorffite, 103.
Gibbsite* (see Note, below).
Giesseckite, 220.
Gigantolite, 266.
Gilbertite, 215.
Gillingite (Hisingerite), 218.
Giobertite, 138.
Girasol, 202.
Gismondiiie, 271.
Glagerite, 220.
Glaserite, 153.
Glauberite, 153.
Glauber's Salt, 153.
Glaucodot, 103.
Glauconite, 259.
Gla'ucophane, 244.
Glingite, 204.
Glockerite, 158.
Gmelinite, 271.
Gcethite, 125.
Gold, 116.
Gold- Amalgam, 115.
Goschenite (v. Beryl).
* Accidentally omitted from foot of page 220, where it should follow Kollyrite :
GIBBSITE (Hydrargillit.-) :— AJ«O' 65-5, WO 34'5. In small hexagonal crystals with basal
cleavage, or in mammary or stalactitic. examples of a white, greenish-yellow, or other light
colour. II 2-5-30; G '2-3-2'4. BB, infusible, but commonly exfoliates. In powder, dissolved
by caustic potash ; also by sulphuric acid.
284
INDEX.
Goslarite, 155.
Grahamite, 122.
Gramenite, 218.
Grammatite, 243.
Graphic Tellurium, 113.
Graphite, 117.
Green Carb. Couper, 135.
Green Earth, 258.
Green Vitriol, 156.
Grey Antimony Ore, llO, 112.
Grey Copper Ore (Tetrahedrite),
110.
Greenockite, 151.
Greenovite Sphene), 229.
Grengesite (near Delessite), 257.
Grophite, 215.
Groroih'te, 188.
Grossular, 241.
Guadalcazarite, 106, 107.
Guanajuatite, 106.
Guarinite, 239.
Gummite, 190.
Gurhofian, 138.
Gymnite, 221
Gypsum, 155, 161.
Gyrolite ( ApophyUite ? ), '267.
Haarkies (Millerite), 105.
Haematite, 118, 120, 114, 128.
Haidingerite, 146.
Halite (Rock Salt), 174, 177.
Hallite, 262.
Halloysite, 220.
Halotrichite, 157.
Harmatite, 179.
Harmatome, 264, 274.
Harringtonite, 266.
Hartite, 133.
Hatchettine, 133.
Hauerite, 108, 124, 152.
Hausmannite, 125.
Hauyne, 246.
Haydenite, 268.
Haytorite (Quartz in pseudo-
morphs after Datolite).
Heavy Spar, 152, 160.
Hebronite, 164.
Hedenbergite, 232.
Hedyphane, 144.
Heliotrope (Bloodstone), 208.
Helminthite, 214.
Helvine, 229.
Helvetaue, 261.
Hematite, 118, 120, 124, 128.
Hercynite, 198.
Herderite, 164.
Herrerite, 137.
Herschelite, 268.
Hessite, 113.
Hessonite (Garnet).
Heterogenite, 189.
Heterosite, 166.
Heulandite, 269, 278.
Hjelmite, 127.
Hisingerite, 218, 258.
Hoernisite, 146.
Homichline, 105.
Hopeite, 168.
Horbachite, 105.
Hornblende, 233.
Horn Silver Ore, 175, 177.
Horseflesh Ore, 108.
Hortonolite, 284.
Hovite, 139.
Hubnerite (Wolfram).
Humboldtilite, 238.
Humboldtine, 187,
Humboldtite, 270.
Humite, 204
Hunterite, 219.
Hureaulite, 166.
Hyacinth, 198.
Hyalite, 209.
Hyalophane, 236, 246.
Hyalosiderite, 228.
Hydrargillite (see Foot-note to
Gibbsite).
Hydroboracite, 172.
Hydrocuprite, 189.
Hydrodolomite, 139.
Hydrofluocerite, 139.
Hydrohematite, 125.
Hydromagnesite, 138.
Hydrophane (var. Opal).
Hydrotachylite, 273.
Hydrozincite, 139.
Hypersthene, 232.
Iberite, 220.
Ice-spar (var. Orthoclase).
Iceland Spar (var. Calcite).
Idocrase, 244, 249.
Idrialine, 130.
Iglesite, 135.
Ilmenite, 118, 120, 125, 128,
186, 192.
Ilvaite, 228, 250.
Indicolite, 199.
lodargyrite, 175.
lolite, 200, 211.
Iridium, 117.
Iridosrnine, 117.
Iridosmium, 117.
Iron, 117.
Iron Alum, 157.
Iron Chrysolites, 250.
INDEX.
285
Iron Glance, 118, 120.
Iron Pyrites, 105, 108.
Ironstone, 140.
Isoclase, 168.
Ittiierite, 270.
Ixolyte, 132.
Jacobsite, 118, 186.
Jamesonite, 111, 112.
Jargon (Zircon), 198.
Jarosite, 159.
Jasper, 208.
Jeflerisite, 362.
Jeffersoiiite, 233.
Jenite (Lievrite), 228, 250.
Jet, 132.
Johannite, 157.
Jordanite, 104.
Kammercrite, 214.
Kalaite (Turquoise).
Koinite, 154.
Kakoxene, 165.
Kalinite, 154.
Kampylite, 144.
Kaolin, 219, 225.
Karminspath, 144.
Karstenite (Anhydrite), 152.
Kastor, 215.
Keilhauite, 230.
Kenngottite (var. Miargyrite).
Keragyrite, 175, 177.
Kerasine, 135, 176.
Kermesite, 121, 123, 149.
Kerolite, 221.
Kibdelophane (Ilmenite), 118.
Kieserite, 155.
Kilbrickenite, 112.
Killiiiite, 262.
Kirwanite, 260,
Kjerulfine, 163.
Klaprothiiie (Lazulite), 168.
Klipsteinite, 264.
Knebelite, 229.
Kobellite, 112.
Kosttigite, 145.
Kollyrite, 220.
Konite, 130.
Kottigite, 145.
Kongsbergite, 115.
Koiileinite, 133.
Korundophyllite, 214.
Koupholite, 267.
Krantzite, 132.
Kraurite (Green Iron Ore, an
iron phosphate).
Kreittonite, 197.
Kremersite, 175.
Krisuvigite, 158.
Krokidolite, 259.
Kuhnite, 146.
Kyanite, 197.
Labradorite, 241.
Labrador Feldspar, 241.
Lagonite, 172.
Lampadite, 189.
Lanarkite, 151.
Lancasterite, 139.
Langite, 158.
Lanthanite, 139.
Lapis Lazuli, 237.
Larderellite, 172.
Latrobite (var. Anorthite).
Launiontite, 272, 277.
Laxmannite, 182.
Lazulite, 168.
Lead, 115.
Lead Binnite, 104.
Lead Glance, 107, 109.
Leadhillite, 135.
Leafy Tellurium Ore, 111.
Lehrbachite, 106.
Lehuntite, 266.
Lenzinite, 220.
Leonhardite, 272.
Lepidochrocite, 125, 187.
Lepidokrokite, 125, 187.
Lepidolite, 230, 234, 247.
Lepidomelane, 227.
Lettsomite, 158.
Leuchtenbergite (Ripidolite),
214.
Leucite, 203, 212.
Leucophane, 178, 240.
Leucopyrite, 101.
Levyne, 268.
Libethenite, 167, 170.
Liebenerite, 220.
Liebigite, 139.
Lievrite, 228, 250.
Lignite, 132.
Ligurite (Sphene), 229.
Lillite, 257.
Lime Uranite, 166.
Limonite, 125, 128.
Linarite, 158.
Lincolnite, 269.
Lindakerite, 139.
Linno3ite, 105.
Liroconite, 144, 147.
Litharge, 187.
Lithia Mica, 234.
Liver Ore, 131.
Lobolite, 245.
Lollingite, 101.
28*
INDEX.
Lcewite, 154.
Loxoclase (var. Orthoclase).
Ludlamite, 165.
Ludwigite, 171.
Lutiebergite, 168.
Lunnite (Phosphorchalcite), 167.
Luzonite, 103.
Magnesia Alum, 154.
Magnesite, 138, 140.
Magnetic Iron Ore, 118, 120,
124, 128, 186.
Magnetic Pyrites, 105, 108.
Magnetite, 118, 120, 124, 128,
186.
Magnoferrite. 186.
Malachite, 135, 142.
Malacolite, 243.
Malakon, 198.
Maldonite ( = Bismuthic Gold).
Mangan Blende (Alabandine,
124).
Manganite, 119, 120, 125.
Manganese Alum, 158.
Manganese Spar, 137.
Manganese Vitriol, 158.
Marble, 140.
Marcasite, 105, 108.
Margarite, 215.
Margarodite, 261.
Marmatite, 151.
Marmolite, 221.
Martite, 118.
Mascagnine, 153.
Maskelynite ( = Meteoric Labra-
dorite).
Masonite, 259.
Massicot, 187.
Matlockite, 176.
Maxite, 135.
Medjidite, 157.
Meerschaum, 221.
Mcgabromite, 175.
Meionite, 240.
Melaconite, 189.
Melanglance, 110.
Melanite (Black Garnet).
Melanolite, 258.
Melanochroite (Phoenicite), 182.
Melanterite, 156.
Melilite, 238.
Melinophane, 178, 240.
Meliphanite, 178, 240.
Meionite, 114.
Melopsite (near Deweylite),
221.
Menaccanite, 118.
Mendipite, 176.
Meneglmite, 111.
Mengite, 126.
Menilite, 202.
Mennige, 187.
Mercury, 115.
Mesitine, 136.
Mesolite, 266.
Mesotype, 265.
Metabrushite, 168.
Metachlorite, 214, 256.
Metacinnabarite, 107.
Metaxite, 221.
Meteoric Iron, 117.
Miargyrite, 110, 121.
Micas, 213, 224.
Microbromite, 175.
Microcline, 246.
Microlite (Pyrochlore), 126.
Microsommite, 237.
Millerite, 105.
Miloschin, 218.
Mimetesite, 144, 148.
Minium, 187.
Mirabilite, 153.
Mispickel, 103, 104.
Mizzonite, 241.
Molybdenite, 107, 109.
Molybdic Ochre, 183.
Monazite, 165.
Monrolite, 200.
Montebrasite, 164.
Moiiticellite, 204.
Moonstone ( = Opalescent Feld-
spar).
Morenosite, 157.
Moroxite (var. Apatite), 163.
Mosandrite*
Mottramite, 184.
Mountain Cork, 258.
Mountain Wood, 258.
Miillerine, 113.
Mimetic, 105.
* Accidentally omitted from Table XXVII., immediately following Heulandite, as annexed :
(H 4'0 ; streak distinctly yellow or brownish; decomposed l>y hydrochloric acid with
production of chlarin e fum cs).
MOSANDKITE :— Essential components: Na2O, CaO, MnO, Cc203 with Di2O3 and La208, TiO2,
SiO2, H2O. Rhombic (?), but mostly in broad-fibrous or lameUar masses of a reddish-brown
colour; G 2'9-3'0. BB intumesces and fuses readily into a yellowish-brown bead. The hydro-
rhloric-acid solution is reddish-yellow, but becomes paler, and evolves chlorine, on heating.
A very rare species.
INDEX.
287
Muromontite, 228.
Muscovite, 213, 224.
Nacrite, 219.
Naclorite, 150.
Nagyagite, 111.
Nantokite, 175.
Nasturane, 127.
Native Antimony, 113.
N. Arsenic, 101, 102.
N. Bismuth, 101, 115.
N. Copper, 116.
N. Gold, 116.
N. Iridium, 117.
N. Iron, 117.
N. Lead, 115.
N. Mercury, 115.
N. Palladium, 117.
N. Platinum, 117.
N. Silver, 116.
N. Sulphur, 130.
N. Tellurium, 113.
Natrolite, 235, 274.
Natron, 138.
Naumanm'te, 106.
Needle Ore, 107.
Neftgil, 133.
Nemalite, 190.
Nepheline, 239.
Nephrite, 243.
Newjanskite, 117.
Nickel Glance, 110.
Nickel Green, 145.
Nickel Gymnite, 217.
Nickel Vitriol, 157.
Nickeline, 101, 102.
Nigrescite, 260.
Nigrine, 127.
Niobite (Coluuibite), 126.
Nipholite, 178.
Nitratiiie, 181.
Nitre, 181.
Nitrocalcite, 181.
Nitromagnesite, 181.
Nontronite, 218.
Nosean, 236.
Nosine, 236.
Nuttalite, 241.
Obsidian, 247.
Ochres :
Bismuth 0., 188.
Manganese 0. (Wad), 188.
Molybdic, O,, 183.
Bed 0., 186, 192.
Tungstic 0., 183.
UranO., 190.
Yellow 0., 187.
Octahedrite, 127, 199.
(Ellacherite, 261.
Oerstedite, 198.
Okenite, 268.
Olafite, 246.
Oligoclase, 246.
Oligon Spar, 136.
Olivenite, 143, 147.
Olivine, 204, 210.
Omphazite (Var. Pyroxene).
Onkosine (compact magnesian
mica? Related to Phlogo-
pite or Biotite, as Steatite
to Talc).
Onofrite, 106.
Onyx (Agate), 208.
Opal, 202, 208.
Ophiolite, 225.
Orangite, 218.
Orpiment, 130, 131.
Orthite, 228.
Orthoclase, 245, 253.
Osmelite (Pectolite?), 265.
Osinium-Iridium, 117.
Osteolite, 163.
Ostranite, 198.
Ottrelite, 259.
Ouvarovite, 198.
Owenite, 256.
Oxalite, 187.
Oxhaverite, 268.
Ozarkite, 272.
Ozokerite, 133.
Pachnolite, 178.
Palagonite, 257.
Palladium, 117.
Paper Coal, 132.
Paraffme, 133.
Paragonite, 261.
Paranthine, 240.
Pargasite, 233.
Parisite, 179.
Passauite, 241.
Patrinite (Aikinite), 107.
Paulite (v. Hypersthene), 232.
Pearl Mica, 215.
Pearl Spar (Dolomite).
Peaiistone, 247.
Pectolite, 265.
Peganite, 167.
Pegmatolite, 245.
Pelicanite, 219.
Pelokonite, 189.
Pennine, 214.
Percy lite, 176.
288
INDEX.
Periclase, 190.
Pericline, 246, 255.
Peridot, 204.
Peristerite, 246.
Perowskite, 126.
Perthite, 245.
Petalite, 235.
Petroleum, 132.
Petzite, 113.
Phacolite, 268, 278,
Phsestine (Altered Bronzite).
Pharmacolite, 146, 148.
Pharmacosiderite, 145, 148.
Phenakite, 200.
Phengite (Muscovite).
PhiUipsite, 270, 276.
Phlogopite, 213, 224.
Phoenicite, 182.
Pholerite, 219.
Phosgenite, 135, 176.
Phosphocerite, 164.
Phosphorchalcite, 167, 170.
Phosphorite, 163
Phyllite (Ottrelite ?), 259.
Physalite, 197.
Piauzite, 132.
Pickeringite, 154.
Picotite (Chroiniferous Spinel).
Picrolite, 221.
Picrophyll, 215.
Picrosmine, 221.
Piedmontite, 231.
Pilinite (asbestifonnampliibole?)
Pimelite, 217.
Pinguite, 218.
Pinite, 220.
Pinite group, 226.
Pisanite, 157.
Pissophane, 158.
Pistacite, 231.
Pistoniesite, 136.
Pitchblende, 127, 190.
Pitchstone, 247.
Pittizite, 146.
Plagionite, 111.
Planerite, 167.
Plasma (Green Calcedony).
Platinum, 117.
Platinum-Iridium, 117.
Platinum-Iron, 117.
Plattnerite, 122.
Pleonaste, 197.
Plmian, 103.
Plumbago, 117.
Plumbo-Calcite, 135.
Plumosite (Jamesonite).
Poliauite, 119.
PoUux, 203.
Polyadelphite (var. Garnet).
Polyargyrite, 110.
Polybasite, 104, 110, 121, 143.
Poly erase, 126.
Poly dy mite, 105.
Polyhalite, 156, 161.
Polymignite, 126.
Polyxene (N. Platinum).
Poonahlite, 272.
Porcelain Earth (Kaolin), 219.
Prase, 208.
Prascolite, 220,
Prasiiie (Ehlite), 166.
Pregrattite, 261.
Prehnite, 267.
Prochlorite, 214.
Prosopite, 179.
Proustite, 121, 123, 143. 147.
Przibramite, 129.
Pseudomalachite (Phosphor-
chalcite), 167.
Pseudophite (Compact Chlorite).
Psilomelane, 119, 125, 193.
Psittacinite, 184.
Pucherite, 182.
Purple Copper Pyrites, 105, 108.
Puschkinite (Epidote).
Pycnite, 197.
Pycnotrope, 263.
Pyrallolite, 222.
Pyrargillite, 220.
Pyrargyrite, 110, 112, 121, 123.
Pyreneite (Black Garnet).
Pyrgom, 232.
Pyrites :
Arsenical Pyrites.
Capillary Pyrites (Millerite),
105.
Cockscomb Pyrites, 108.
Copper Pyrites, 105.
Iron Pyrites, 105, 108.
Magnetic Pyrites, 105, 108.
Purple Copper Pyrites, 105.
Radiated Pyrites (Marca-
site), 105.
Spear Pyrites, 108.
White Iron Pyrites (Mar-
casite), 105, 108.
Pyrochlore, 126.
Pyrochroite, 189, 191.
Pyrolusite, 119, 120, 125, 193,
Pyromorphite, 163, 169.
Pyrope, 231.
Pyrophyllite, 214.
Pyrophysalite (Pycnite), 197.
Pyropissite, 132.
Pyrosclerite, 264.
Pyrosmalite, 257.
INDEX.
289
Pyrostibite, 149.
Pyrostilpnite, 149.
Pyroxene, 232, 243, 250.
Pyrrhite (Pyrochlor ?).
Pyrrhosiderite (Gcethite), 187.
Pyrrhotine, 105, 108,
Quartz, 202, 208.
Quicksilver, 115,
Rabdionite, 189.
Radiated Pyrites (Marcasite),
105.
Radiolite, 266.
Rammelsbergite, 101.
Randanite, 202.
Raphilite (var. Amphibole).
Ratofkite, 178.
Realgar, 130, 131.
Red Antimony Ore, 121, 123,
149.
Red Copper Ore, 116, 189.
Red Hematite, 186, 192.
Red Iron Ore, 186, 192.
Red Lead, 187.
Red Ochre, 186, 192.
Red Silver Ores, 121, 123, 147.
Red Zinc Ore (Zincite), 188, 193.
Reddle, 192.
Redruthrite (Copper Glance),
106.
Remingtonite, 139.
Rensselaerite (Pseudomorphous
Steatite).
Retinalite, 221.
Retinite, 132.
Reussin, 154.
Rhcetizite (Kyanite), 197.
Rhagite, 145.
Rhodizite, 171.
Rhodochrosite. 137, 141.
Rhodonite, 233.
Richmondite, 167.
Rionite, 112.
Ripidolite, 214.
Rittingerite, 102, 104, 121, 143.
Rivotite, 150.
Rock Crystal, 202, 208.
Rock Salt, 174, 177.
Romerite, 157.
Ropperite, 137.
Rottistite, 217.
Romanzovite (var. Garnet).
Romeite, 150.
Roscoelite, 213.
Rose Quartz, 208.
Roselite, 145.
RubeUane, 261.
20
Rubellite, 199.
Ruby, 196, 207. '
Ruby Blende (Red Silver Ores),
147.
Ruby Copper (Red Copper Ore),
189.
Ruby Silver (Red Silver Ores),
121, 123, 147.
Rutile, 127, 129, 198, 206.
Ryacolite, 245.
Sagenite (var. Rutile).
Sahlite, 232, 243.
Salammoniac, 174.
Salamstone (var. Corundum).
Salmiac, 174.
Saltpetre, 181.
Salt, 174.
Samarskite, 126, 196.
Sanidine, 245.
Sapphire, 196, 297.
Sapphirine, 197.
Sarcolite, 239.
Sardianite, 151,
Sartorite, 104.
Sassoline, 171.
Saynite, 105.
Scapolite, 240, 252.
Scheelite, 183, 185.
Scheererite, 133.
Schiller-spar, 215.
Schorl, 231, 248.
Schorlomite.
Schroetterite, 262.
Schreibersite (Meteoric Iron
Phosphide).
Schwartzembergite, 176.
Scleroelase, 104.
Scoleeite, 272, 277.
Scorodite, 146.
Scoulerite, 272.
Seebachite, 268.
Seladonite, 258.
Selenite, 155, 161.
Sellaite, 178.
Senarmontite, 159.
Sepiolite, 221.
Serbian, 218.
Sericite, 261.
Serpentine, 221, 225.
Serpentine Group, 225.
Seybertite (Clintonite) 219.
Siderite, 136, 140,
Sideromelane, 228.
Sideroplesite, 136.
Sideroschisolite (Cronstedtite),
256.
Sieburgite, 132.
29:
INDEX.
Xanthite, 245.
Xanthacone, 143.
Xanthophyllite, 216.
Xanthosiderite (var. Brown
Iron Ore).
Xenolite, 200.
Xenotime, 164.
Xylite, 260.
Xylotile, 258.
Yellow-Ochre, 187.
Yttrocerite, 179.
Yttrotantalite, 127.
Yttrotitanite, 230.
Zalpaite, 107.
Zaratite, 139.
Zeagonite, 271.
Zeolites, 273 to 278.
.Zepharovichite, 167.
Zeunerite, 144.
Ziegenite, 105.
Zinc Blende, 108, 109, 124, 129,
151, 159.
Zinc Bloom, 139.
Zincite, 188, 193.
Zinc Spar, 137.
Zinc Vitriol (Goslarite), 155.
Ziukenite, 111.
Zippeite, 157.
Zircon, 198, 207.
Zoisite, 244, 249.
Zorgite, 106.
Zwieselite, 164.
Zygadite, 246.
COPP, CLARK <fc CO., PRINTERS, C >LBORNE STREET, TORONTO.
UNIVERSITY OF CALIFORNIA LIBRARY
BERKELEY
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